JP4534597B2 - Infrared radiation element - Google Patents

Description

  The present invention relates to an infrared radiation element.

  Conventionally, various analyzers using an infrared radiation source (for example, an infrared gas analyzer) are provided, but typical infrared radiation sources used in these analyzers are as follows: Since the halogen lamp is large and has a relatively short life, it is difficult to apply to a small gas sensor that detects gas using infrared rays. Some infrared radiation sources, such as halogen lamps, in which a filament as a radiator is housed in a light-transmitting hermetic container, have been downsized by devising the shape and radiation characteristics of the filament. However, since an airtight container is required, it is difficult to apply to a small gas sensor.

  Therefore, as an infrared radiation source that can be miniaturized, an infrared radiation element formed by utilizing micromachining technology has been researched and developed in various places (for example, see Patent Documents 1, 2, and 3).

  Here, in Patent Documents 1 to 3, a so-called linear heating element is bridged between two points on one surface side of a rectangular frame-shaped support substrate formed by processing a silicon substrate or the like by a micromachining technique. An infrared emitting element with a microbridge structure is described. Note that this type of infrared radiation element having a microbridge structure radiates infrared rays from a heating element by Joule heat accompanying energization of a linear heating element.

  By the way, in order to increase detection accuracy in a gas sensor that detects gas using infrared absorption, it is desirable to stabilize and measure the amount of infrared radiation emitted from the infrared radiation element in a short time. In the infrared radiation element having a bridge structure, the support substrate is formed in a rectangular frame shape, and the periphery of the linear heating element is air, so that the difference in heat capacity between the heating element and the surroundings of the heating element can be increased. It responds at a high speed to the on / off of the current flowing through.

  However, in the infrared radiation elements disclosed in Patent Documents 1 to 3, in order to improve the response speed accompanying the on / off of the voltage applied between the pads provided at both ends of the linear heating element, the periphery of the heating element is arranged. The difference in heat capacity between the heating element and the surroundings is increased as air or vacuum, but the heating element is damaged because the heating element is formed in a linear shape and both ends are supported by the support substrate. In some cases, the service life may be shortened by fusing with heat.

Therefore, as an infrared radiation element that can increase the amount of infrared radiation and increase the lifetime as compared with the infrared radiation elements disclosed in Patent Documents 1 to 3, such as a porous silicon layer. A planar infrared radiation element using a porous layer has been proposed. In this type of planar infrared radiation element, for example, a heat insulating layer made of a first porous silicon layer is formed on one surface side of a silicon substrate, and moreover than the first porous silicon layer on the heat insulating layer. A layered heating element composed of a second porous silicon layer having high thermal conductivity and electrical conductivity is formed, and a pair of pads is formed on the heating element. Here, in a planar infrared radiation element using a porous layer, the relationship between the absolute temperature of the heating element and the peak wavelength of infrared radiation emitted from the heating element satisfies the Wien's displacement law. The second porous silicon layer constitutes a pseudo black body and can emit infrared rays having a peak wavelength of 4 μm or more. Moreover, the planar infrared radiation element using a porous layer has a high-speed response of 10 Hz or more.
Japanese Patent Laid-Open No. 9-153640 (see paragraph numbers [0027] and [0028], FIG. 2) Japanese Unexamined Patent Publication No. 2000-236110 (see paragraph numbers [0017], [0018], [0019], FIG. 1 and FIG. 2) Japanese Patent Laid-Open No. 10-294165 (see paragraph numbers [0014] and [0015], FIG. 1)

  By the way, in the above-described planar infrared radiation element using the porous layer, it is desirable to make the resistance of the heating element lower than the resistance of the heat insulating layer in order to reduce power consumption. A first porous silicon layer and a second porous silicon layer are successively formed on one surface side of a silicon substrate, and then ion implantation is performed on the second porous silicon layer to perform activation annealing. It is conceivable to form a low resistance heating element.

  However, when the present inventors adopt a process of performing ion implantation into the second porous silicon layer and performing activation annealing, the first porous silicon layer is caused by thermal strain at the time of performing activation annealing. It has been found that the layer and the second porous silicon layer may be destroyed, resulting in a decrease in yield. In addition, in the above-described planar infrared radiation element, it has been found that the second porous silicon layer may be damaged due to thermal strain during operation.

  This invention is made | formed in view of the said reason, The objective is to provide the infrared radiation element which can improve the heat resistance at the time of manufacture and operation | movement.

The invention according to claim 1, and a heat insulating layer made of a first porous semiconductor layer having a smaller thermal conductivity than the semiconductor substrate is formed on one surface side of the semiconductor substrate, than the heat insulating layer formed on the heat insulating layer each thermal conductivity and electric conductivity and a calling thermal body made of the large second porous semiconductor layer, an infrared light-emitting element radiates infrared rays from the heating element thereby heating the heating element by energizing the heating element In the first porous semiconductor layer, a low-porosity layer having a small porosity is provided in the middle of the depth direction, and among the first porous semiconductor layers, heat is generated in the first porous semiconductor layer. The portion present in the projection region in the depth direction of the opening surface of each micropore at the interface with the body constitutes a reinforcing structure that reinforces the mechanical strength of the first porous semiconductor layer It is characterized by.

According to the present invention, the heat insulating layer made of the first porous semiconductor layer has the reinforcing structure portion, so that the heat resistance at the time of manufacture and operation is improved, and due to the thermal strain at the time of manufacture and operation. Since it is possible to prevent the heat insulating layer from being damaged, it is possible to improve the manufacturing yield and the reliability.

Further, according to this invention, the first porous semiconductor layer, a small low-porosity layer porosity is provided in the middle of the depth direction, of the first porous semiconductor layer, a first porous The portion present in the projection region in the depth direction of the opening surface of each micropore at the interface with the heating element in the porous semiconductor layer is a reinforcing structure that reinforces the mechanical strength of the first porous semiconductor layer. it means the configuration, it is possible to form a by Riho strong structure to form a low-porosity layer in the middle in the depth direction during the formation of the first porous semiconductor layer.

According to a second aspect of the present invention , there is provided a heat insulating layer made of a first porous semiconductor layer formed on one surface side of a semiconductor substrate and having a thermal conductivity smaller than that of the semiconductor substrate, and a heat conductive layer formed on the heat insulating layer than the heat insulating layer. A heating element comprising a second porous semiconductor layer having a large rate and conductivity, each of which emits infrared rays from the heating element by heating the heating element by energizing the heating element, the first porous semiconductor layer, are formed so as porosity gradually decreases toward the semiconductor substrate Te depth direction odor, of the first porous semiconductor layer, put the first porous semiconductor layer that portion present in the projection region in the depth direction of the opening surface of each micropore at the interface between the outgoing hot body, constituting a reinforcement structure which reinforces the mechanical strength of the first porous semiconductor layer It is characterized by that.

According to the present invention, the heat insulating layer made of the first porous semiconductor layer has the reinforcing structure portion, so that the heat resistance at the time of manufacture and operation is improved, and due to the thermal strain at the time of manufacture and operation. Since it is possible to prevent the heat insulating layer from being damaged, it is possible to improve the manufacturing yield and the reliability. Further , according to the present invention, since the porosity continuously changes in the depth direction of the first porous semiconductor layer , the porosity is stepwise in the depth direction of the first porous semiconductor layer. it is possible to prevent breakage of the cross heat layer more securely as compared with the case where changing.

According to a third aspect of the present invention , there is provided a heat insulating layer made of a first porous semiconductor layer formed on one surface side of a semiconductor substrate and having a thermal conductivity smaller than that of the semiconductor substrate, and a heat conductive layer formed on the heat insulating layer than the heat insulating layer. A heating element comprising a second porous semiconductor layer having a large rate and conductivity, each of which emits infrared rays from the heating element by heating the heating element by energizing the heating element, the first porous semiconductor layer, Yes and smaller than the porosity of the site near the semiconductor substrate to another portion Te depth odor, of the first porous semiconductor layer, a first porous semiconductor reinforcement structure moiety present in the projection region in the depth direction of the opening surface of each micropore at the interface between the outgoing hot body that put in layers, to reinforce the mechanical strength of the first porous semiconductor layer It comprises the part.

According to the present invention, the heat insulating layer made of the first porous semiconductor layer has the reinforcing structure portion, so that the heat resistance at the time of manufacture and operation is improved, and due to the thermal strain at the time of manufacture and operation. Since it is possible to prevent the heat insulating layer from being damaged, it is possible to improve the manufacturing yield and the reliability. Further, according to the present invention, it means that the first porous semiconductor layer porosity nearby small yet the semiconductor substrate than the other sites site constitutes a reinforcement structure, destruction of the cross heat layer occurs easy-semiconductor substrate near the site can be reinforced, cross heat layer can be prevented from being destroyed by thermal strain during fabrication or during operation.

The invention according to claim 4, characterized in that in the invention of claim 3, wherein the first porous semiconductor of the semiconductor substrate near the layer site, porosity gradually decreases as in the depth direction closer to the semiconductor substrate It is characterized by being.

According to this invention, damage to the heat insulating layer can be more reliably prevented as compared with the case where the porosity is changed stepwise as the semiconductor substrate is approached in the depth direction.

According to a fifth aspect of the present invention , there is provided a heat insulating layer made of a first porous semiconductor layer formed on one surface side of a semiconductor substrate and having a lower thermal conductivity than the semiconductor substrate, and a heat conductive layer formed on the heat insulating layer than the heat insulating layer. A heating element comprising a second porous semiconductor layer having a large rate and conductivity, each of which emits infrared rays from the heating element by heating the heating element by energizing the heating element, oxide film along the first porous respective inner surfaces each micropore of the semiconductor layer is formed, the oxide film, constitute a reinforcement structure which reinforces the mechanical strength of the first porous semiconductor layer It is characterized by being.

According to the present invention, the heat insulating layer made of the first porous semiconductor layer has the reinforcing structure portion, so that the heat resistance at the time of manufacture and operation is improved, and due to the thermal strain at the time of manufacture and operation. Since it is possible to prevent the heat insulating layer from being damaged, it is possible to improve the manufacturing yield and the reliability. Further, according to the present invention, it is possible to reinforce the first oxide film a porous semiconductor layer formed along the inner surface of the micropores, the first porous semiconductor that make up the cross heat layer The porosity of the layer can be made uniform, and the formation of the first porous semiconductor layer is facilitated.

In invention of Claims 1-5 , when the heat insulation layer which consists of a 1st porous semiconductor layer has a reinforcement structure part, the heat resistance at the time of manufacture and operation improves, and at the time of manufacture and operation Since it is possible to prevent the heat insulation layer from being damaged by thermal strain, there is an effect that the production yield and the reliability can be improved.

(Embodiment 1)
In the infrared radiation element A of the present embodiment, as shown in FIG. 1, a heat insulating layer 2 having a sufficiently smaller thermal conductivity than the semiconductor substrate 1 is formed on one surface (upper surface in FIG. 1) side of the semiconductor substrate 1. At the same time, a layered heating element 3 having a larger thermal conductivity and conductivity than the heat insulating layer 2 is formed on the heat insulating layer 2, and a pair of pads (electrodes) 4 and 4 for energization are formed on the heat generating body 3. Infrared rays are emitted from the heating element 3 by causing the heating element 3 to generate heat by energizing the heating element 3. Here, the heat insulating layer 2 and the heating element 3 are each composed of a porous semiconductor layer (hereinafter, the porous semiconductor layer constituting the heat insulating layer 2 is referred to as a first porous semiconductor layer, and the heating element 3 The porous semiconductor layer is referred to as a second porous semiconductor layer). However, as the porosity increases, the porous semiconductor layer has a smaller thermal conductivity and heat capacity. For example, the thermal conductivity is 168 [W / (M · K)] and a porous silicon layer having a porosity of 60% formed by anodizing a single crystal silicon substrate having a heat capacity of 1.67 × 10 ⁶ [J / (m ³ · K)] Is known to have a thermal conductivity of 1 [W / (m · K)] and a heat capacity of 0.7 × 10 ⁶ [J / (m ³ · K)]. The pads 4 and 4 are made of a metal material (for example, tungsten, aluminum, gold, etc.). The first porous semiconductor layer has a structure in which a high porosity layer 21 having a high porosity and a low porosity layer 22 having a low porosity are alternately stacked. The porosity and the porosity of the second porous semiconductor layer are set to the same value. In the present embodiment, the semiconductor substrate 1 constitutes a substrate, and the second porous semiconductor layer constitutes a porous layer.

In the infrared radiating element A of the present embodiment, if the peak wavelength of infrared rays emitted from the heating element 3 is λ (μm) and the absolute temperature of the heating element 3 is T (K), the peak wavelength λ is
λ = 2898 / T
Thus, the relationship between the absolute temperature T of the heating element 3 and the peak wavelength λ of infrared rays emitted from the heating element 3 satisfies the Vienna displacement law. In short, in the infrared radiation element A of the present embodiment, the second porous semiconductor layer as the heating element 3 forms a pseudo black body, and the voltage applied between the pads 4 and 4 from an external power source (not shown) is adjusted. As a result, the Joule heat generated in the heating element 3 can be changed, and the peak wavelength λ of the infrared rays emitted from the heating element 3 can be changed. In the infrared radiation element A of the present embodiment, for example, by applying a voltage of about 300 V between the pair of pads 4 and 4, infrared light having a peak wavelength λ of 3 μm to 4 μm can be emitted. It is possible to emit infrared rays having a peak wavelength of 4 μm or more by appropriately adjusting the voltage applied between 4 and 4.

  In the infrared emitting element A of the present embodiment, a single crystal p-type silicon substrate having a main surface (the one surface) of (100) and a resistivity of 100 Ωcm is used as the semiconductor substrate 1. The porous semiconductor layer and the second porous semiconductor layer are each composed of a porous silicon layer. In addition, in the infrared radiation element A of the present embodiment, the thickness of the semiconductor substrate 1 before the formation of the heat insulating layer 2 and the heating element 3 is 625 μm, the thickness of the heat insulating layer 2 formed by anodizing treatment is 50 μm, and anodizing treatment The thickness of the heating element 3 formed by 1 is 1 μm and the thickness of the pad 4 is 0.1 μm. However, these thicknesses are merely examples and are not particularly limited.

  Hereinafter, the manufacturing method of the infrared radiation element A of this embodiment is demonstrated.

First, a current-carrying electrode (not shown) used at the time of anodizing is formed on the other surface (lower surface in FIG. 1) side of the semiconductor substrate 1, and then the heating element 3 is to be formed on the one surface side of the semiconductor substrate 1. And the porous formation process which forms a 2nd porous semiconductor layer and a 1st porous semiconductor layer one by one by making porous the formation scheduled part of the heat insulation layer 2 by an anodizing process. Here, in the anodic oxidation treatment, a mixed liquid in which a 55 wt% aqueous hydrogen fluoride solution and ethanol are mixed at a ratio of 1: 1 is used as an electrolytic solution, and an object to be processed mainly composed of the semiconductor substrate 1 can be put in a treatment tank. A current of a predetermined current density is passed between the anode and the cathode from the power source, with the current-carrying electrode as an anode and the platinum electrode facing the one surface of the semiconductor substrate 1 as a cathode. Thus, the second porous semiconductor layer and the first porous semiconductor layer are continuously formed. However, when each of the high porosity layers 21 in the second porous semiconductor layer and the first porous semiconductor layer is formed, the predetermined current density is set to a relatively large value (for example, 50 mA / cm ² ), and the first The predetermined current density is set to a relatively small value (for example, 5 mA / cm ² ) when each low porosity layer 22 is formed in the porous semiconductor layer. In the present embodiment, the total time for flowing a current having a current density of 50 mA / cm ² is set to 8 minutes, and the time for flowing a current having a current density of 5 mA / cm ² is set in one low porosity layer 22. However, the current density and time are not particularly limited.

After the above-described porous step, a resistance reduction step is performed to reduce the resistance of the heating element 3 to be formed on the one surface side of the semiconductor substrate 1 (that is, the second porous semiconductor layer). Here, in the low resistance process, after performing the ion implantation process of implanting impurity ions from the one surface side of the semiconductor substrate 1 to the second porous semiconductor layer, the semiconductor substrate 1 was implanted into the second porous semiconductor layer. By performing an annealing process for activating impurity ions, the heating element 3 made of the second porous semiconductor layer with reduced resistance is formed. In the low resistance process, the ion implantation conditions are phosphorus, the acceleration voltage is 50 kV, the dose is 1 × 10 ¹⁵ cm ⁻² , the annealing conditions are nitrogen, the annealing temperature is 1000 ° C. Although the annealing time is 30 minutes, the ion implantation conditions and the annealing conditions are both examples and are not particularly limited.

  After the above-described low resistance process, by performing a pad forming process for forming a pad 4 made of a metal material (for example, tungsten, aluminum, etc.) by vapor deposition using a metal mask or the like, the infrared radiation element A is Complete.

  In the manufacturing method described above, the resistance reduction step is performed after the porosification step. However, the resistance reduction step may be performed before the porosity step. A thermal diffusion process may be adopted as the process. Further, a low resistance semiconductor thin film (for example, an n-type amorphous silicon thin film, an n-type silicon epitaxial layer, etc.) is formed on the one surface of the semiconductor substrate 1 before the porous step, by various CVD methods, sputtering methods, lasers, etc. The heating element 3 may be formed by forming a film by an ablation method, an epitaxial growth method, or the like, and making the semiconductor thin film porous in the porous step. In the manufacturing method described above, ion implantation is performed on the entire surface of the semiconductor substrate 1 on the one surface side. However, a portion other than a region where the heating element 3 is to be formed is masked with a mask layer such as a silicon oxide film or a resist film. It goes without saying that ion implantation may be performed after that.

  In the infrared emitting element A of the present embodiment described above, the low porosity layer 22 having a small porosity is provided in the middle of the depth direction of the first porous semiconductor layer constituting the heat insulating layer 2, and the first porous Of the porous semiconductor layer, the portion existing in the projection region in the depth direction of the opening surface of each micropore 2a at the interface with the heating element 3 in the first porous semiconductor layer is the first in the depth direction. The reinforcing structure 5 is configured to reinforce the mechanical strength of the first porous semiconductor layer as compared with the case where the porosity of the porous semiconductor layer is made uniform.

  Thus, in the infrared radiation element A of the present embodiment, the heat insulating layer 2 has the reinforcing structure portion 5 that reinforces the mechanical strength as compared with the case where the porosity is uniform in the depth direction. The heat resistance during operation is improved, and the heat insulating layer 2 can be prevented from being damaged by thermal strain during production or operation, so that the production yield and the reliability can be improved. In addition, since a part of the low porosity layer 22 constitutes the reinforcing structure portion 5, the low porosity layer 22 is formed in the middle of the depth direction during the formation of the first porous semiconductor layer. The structure part 5 can be formed.

(Embodiment 2)
The basic configuration of the infrared radiation element A of the present embodiment is substantially the same as that of the first embodiment. As shown in FIG. 2, the structures of the heat insulating layer 2 and the reinforcing structure 5 are different, and the other configurations are the same as those of the first embodiment. The description is omitted because it is the same.

  The heat insulating layer 2 in the infrared radiation element A of the present embodiment is formed so that the porosity gradually decreases as it approaches the semiconductor substrate 1 in the depth direction, and the first porous semiconductor layer constituting the heat insulating layer 2 is formed. Among these, the portion existing in the projection region in the depth direction of the opening surface of each micropore 2a at the interface with the heating element 3 in the first porous semiconductor layer is the first porous semiconductor in the depth direction. The reinforcing structure 5 is configured to reinforce the mechanical strength of the first porous semiconductor layer as compared with the case where the layer has a uniform porosity.

  Therefore, in the infrared radiation element A of the present embodiment, the porosity continuously changes in the depth direction of the first porous semiconductor layer, so that it is porous in the depth direction of the first porous semiconductor layer. The damage of the heat insulating layer 2 can be more reliably prevented as compared with the case where the degree changes stepwise.

The manufacturing method of the infrared radiation element A of the present embodiment is substantially the same as the manufacturing method described in the first embodiment, and the current density is gradually reduced during the formation of the first porous semiconductor layer in the porous process. The current density is reduced from a relatively large current density (for example, 100 mA / cm ² ) to a relatively small current density (for example, 5 mA / cm ² ) over a predetermined time (for example, 10 minutes). I'll do it.

  In addition, in the infrared radiation element A of the present embodiment, the porosity of the heat insulating layer 2 is continuously reduced in the depth direction, but the low porosity layer 22 similar to that of Embodiment 1 is provided in the middle of the depth direction. The provided structure may be adopted.

(Embodiment 3)
The configuration of the infrared radiation element A of the present embodiment is substantially the same as that of the first embodiment. As shown in FIG. 3, the structures of the heat insulating layer 2 and the reinforcing structure 5 are different, and other configurations are the same as those of the first embodiment. Since it is the same, description is abbreviate | omitted.

  The heat insulating layer 2 in the infrared radiation element A of the present embodiment has a lower porosity in a portion near the semiconductor substrate 1 in the depth direction than other portions, and the first porous layer constituting the heat insulating layer 2 Of the semiconductor layer, the portion existing in the projection region in the depth direction of the opening surface of each micropore 2a at the interface with the heating element 3 in the first porous semiconductor layer is the first in the depth direction. The reinforcing structure 5 is configured to reinforce the mechanical strength of the first porous semiconductor layer as compared with the case where the porosity of the porous semiconductor layer is uniform.

  Therefore, in the infrared radiation element A of the present embodiment, the portion near the semiconductor substrate 1 in the first porous semiconductor layer that has a lower porosity than the other portions constitutes the reinforcing structure 5. It is possible to reinforce a portion near the semiconductor substrate 1 where the heat insulating layer 2 is likely to break down, and to prevent the heat insulating layer 2 from being broken due to thermal strain during manufacturing or operation. Here, the portion of the first porous semiconductor layer near the semiconductor substrate 1 is formed so that the porosity gradually decreases as it approaches the semiconductor substrate 1 in the depth direction. As compared with the case where the porosity is changed stepwise as it approaches 1, damage to the heat insulating layer 2 can be prevented more reliably.

  In the infrared radiation element A of the present embodiment, a structure in which the low porosity layer 22 is provided in the middle of the depth direction may be adopted as in the first embodiment.

(Embodiment 4)
The basic configuration of the infrared radiation element A of the present embodiment is substantially the same as that of the first embodiment. As shown in FIG. 4, the structures of the heating element 3, the heat insulating layer 2, and the reinforcing structure 5 are different. Since it is the same as Embodiment 1, description is abbreviate | omitted.

  In the heat insulating layer 2 in the infrared radiation element A of the present embodiment, a thin oxide film (silicon oxide film in this embodiment) 6 is formed along the inner surface of each fine hole 2a, and each oxide film 6 is a reinforcing structure portion. 5 is constituted. The oxide film 6 is also continuously formed on the inner surfaces of the micropores of the low-resistance second porous semiconductor layer constituting the heating element 3.

  Thus, in the infrared radiation element A of the present embodiment, the first porous semiconductor layer can be reinforced by the thin oxide film 6 formed along the inner surface of each micropore 2a, so that the heat insulating layer 2 is configured. The first porous semiconductor layer can be made porous under the condition (constant current density) that makes the porosity of the first porous semiconductor layer uniform, and the formation of the first porous semiconductor layer is facilitated.

As a method for forming the oxide film 6, a thermal oxidation method is also conceivable. However, when the thermal oxidation method is employed, the thin oxide film 6 is not uniformly formed along the inner surface of the micro hole 2a, and the surface of the micro hole 2a is near the surface. In order to form a thin oxide film 6 uniformly over the entire inner surface of the fine hole 2a, an electrochemical oxidation method or an oxidation property is used. It is desirable to employ a plasma oxidation method using gas, an oxidation method using ozone, or the like. Here, when an electrochemical oxidation method is employed, the electrolyte solution is changed to a sulfuric acid solution continuously after completion of the porosification step using a mixed solution of hydrogen fluoride aqueous solution and ethanol as the electrolyte solution. Can be processed automatically. As an example of the electrochemical oxidation method, a 1M sulfuric acid solution is used as an electrolytic solution. Similarly to the anodizing treatment, a current-carrying electrode is used as an anode, and a platinum electrode disposed opposite to the one surface side of the semiconductor substrate 1 is used. As a cathode, when a current of a predetermined current density (for example, ² mA / cm ² ) is passed between the anode and the cathode from the power source, the potential between the anode and the cathode is increased by 20 V from the value at the start of energization. What is necessary is just to complete | finish a process.

  By the way, in each said embodiment, although Si is employ | adopted as a material of the semiconductor substrate 1, the material of the semiconductor substrate 1 is not restricted to Si, For example, by anodic oxidation process, such as Ge, SiC, GaP, GaAs, and InP Other semiconductor materials that can be made porous may be used.

1 is a schematic cross-sectional view of an infrared radiation element in Embodiment 1. FIG. 6 is a schematic cross-sectional view of an infrared radiation element in Embodiment 2. FIG. It is a schematic sectional drawing of the infrared rays radiating element in Embodiment 3. It is a schematic sectional drawing of the infrared rays radiating element in Embodiment 4.

Explanation of symbols

A Infrared Radiation Element 1 Semiconductor Substrate 2 Heat Insulating Layer 2a Micropore 3 Heating Element 4 Pad 5 Reinforcing Structure 21 High Porous Layer 22 Low Porous Layer

Claims (5)

And a small thermal conductivity than the semiconductor substrate is formed on one surface side of the semiconductor substrate a first porous semiconductor made of layer insulation layer is formed on the heat insulating layer respectively the thermal conductivity and conductivity than the heat insulating layer and a calling thermal body is made of large second porous semiconductor layer, the infrared from the heating element by generating heat a heating element by energizing the heating element is an infrared light-emitting element is emitted, a first The porous semiconductor layer is provided with a low-porosity layer having a small porosity in the middle of the depth direction, and each of the first porous semiconductor layers at the interface with the heating element in the first porous semiconductor layer. Infrared radiation element characterized in that the portion existing in the projection region in the depth direction of the opening surface of the fine hole constitutes a reinforcing structure portion that reinforces the mechanical strength of the first porous semiconductor layer . A heat insulating layer formed of a first porous semiconductor layer formed on one surface side of the semiconductor substrate and having a lower thermal conductivity than the semiconductor substrate, and a thermal conductivity and a conductivity higher than the heat insulating layer formed on the heat insulating layer. An infrared light emitting device that includes a heating element including a second porous semiconductor layer and emits infrared rays from the heating element by causing the heating element to generate heat by energizing the heating element. It is formed so as porosity gradually decreases toward the semiconductor substrate in the depth direction, of the first porous semiconductor layer, each at the interface between the outgoing hot body in the first porous semiconductor layer moieties present in the projection region in the depth direction of the opening surface of the micropores, characterized in that it constitutes a reinforcement structure which reinforces the mechanical strength of the first porous semiconductor layer red External radiation element. A heat insulating layer formed of a first porous semiconductor layer formed on one surface side of the semiconductor substrate and having a lower thermal conductivity than the semiconductor substrate, and a thermal conductivity and a conductivity higher than the heat insulating layer formed on the heat insulating layer. An infrared light emitting device that includes a heating element including a second porous semiconductor layer and emits infrared rays from the heating element by causing the heating element to generate heat by energizing the heating element. the portions of the semiconductor substrate near Te depth direction odor porosity Yes made smaller than other portions, of the first porous semiconductor layer, the outgoing heat body according to the first porous semiconductor layer wherein the portion present in the projection region in the depth direction of the opening surface of each micropore at the interface constitutes a reinforcement structure which reinforces the mechanical strength of the first porous semiconductor layer infrared radiation element shall be the. 4. The infrared radiation element according to claim 3 , wherein a portion of the first porous semiconductor layer near the semiconductor substrate has a gradually decreasing porosity as it approaches the semiconductor substrate in the depth direction. 5. . A heat insulating layer formed of a first porous semiconductor layer formed on one surface side of the semiconductor substrate and having a lower thermal conductivity than the semiconductor substrate, and a thermal conductivity and a conductivity higher than the heat insulating layer formed on the heat insulating layer. An infrared light emitting device that includes a heating element including a second porous semiconductor layer and emits infrared rays from the heating element by causing the heating element to generate heat by energizing the heating element. oxidized film is formed along each micropore respective internal surface of each oxide film, characterized in that it constitutes a reinforcement structure which reinforces the mechanical strength of the first porous semiconductor layer red External radiation element .

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