JP6398591B2 - Electronic equipment - Google Patents

Description

  The technology disclosed in this specification relates to an electronic device. In particular, the technology disclosed in this specification relates to an electronic device including a channel portion including a phase change material that causes a phase transition between a metal phase and an insulator phase.

  Development of an electronic device using a phase transition material that undergoes a phase transition between a metal phase and an insulator phase is in progress. Patent Document 1 discloses an electronic device in which this type of phase change material is applied to a channel portion. This electronic device is configured to control the phase transition of the phase transition material in the channel portion. When the phase transition material is a metal phase, a current is passed through the channel portion, and when the phase transition material is an insulator phase, the channel is It operates to cut off the current of the part.

JP 2011-243632 A

  The electronic device disclosed in Patent Document 1 is configured to inject a high-concentration charge from an ionic liquid into the channel portion in order to cause a phase transition in the phase change material in the channel portion. For this reason, this electronic device requires an enclosing structure for enclosing the ionic liquid in contact with the channel portion. However, it is technically difficult to construct a sealing structure that can stably seal an ionic liquid over a long period of time. An object of the present specification is to provide a technique for improving reliability in an electronic device including a channel portion including a phase change material.

  One embodiment of the electronic device disclosed in the present specification includes a channel unit and a temperature rise generation unit. The channel portion includes a phase change material that changes phase between a metal phase and an insulator phase due to a temperature change. The temperature increase generation unit is configured to increase the temperature of the channel unit.

  In the electronic device of the above-described embodiment, the temperature increase generation unit increases the temperature of the channel unit, so that a phase transition can be caused in the phase change material of the channel unit. In the electronic device of the above embodiment, phase transition can be caused in the channel portion without using an ionic liquid. For this reason, the electronic device of the said embodiment can have high reliability.

The principal part sectional drawing of the electronic device of 1st Example is typically shown. One process of the method for manufacturing the electronic device of the first embodiment is shown. One process of the method for manufacturing the electronic device of the first embodiment is shown. One process of the method for manufacturing the electronic device of the first embodiment is shown. One process of the method for manufacturing the electronic device of the first embodiment is shown. One process of the method for manufacturing the electronic device of the first embodiment is shown. One process of the method for manufacturing the electronic device of the first embodiment is shown.

  The technical features disclosed in this specification will be summarized below. The items described below have technical usefulness independently.

  One embodiment of the electronic device disclosed in this specification may include a channel unit and a temperature rise generation unit. The channel portion includes a phase change material that changes phase between a metal phase and an insulator phase due to a temperature change. The temperature increase generation unit is configured to increase the temperature of the channel unit.

  The channel portion refers to a current path through which current flows. An electronic device disclosed in this specification is configured to exhibit a specific function by controlling a current flowing through a channel portion. Typically, the electronic device disclosed herein can operate as a transistor that performs a switching function.

  The phase transition material included in the channel part is not particularly limited as long as it undergoes a phase transition between the metal phase and the insulator phase due to a temperature change. For example, the phase transition material includes d-block transition elements (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf. , Ta, W, Re, Os, Ir, Pt, Au), it is desirable that the oxide Mott insulator. Such a phase change material can effectively phase change between the metal phase and the insulator phase due to temperature change.

  The temperature rise generation unit is not particularly limited as long as it is configured to increase the temperature of the channel unit. The temperature increase generation unit may be configured to increase the temperature of the channel unit using various optical, electrical, chemical, or mechanical methods.

  For example, the temperature rise generation unit may include a light emitting element. In this case, the temperature increase generation unit can increase the temperature of the channel part using the light energy of the light from the light emitting element. Although the kind of light emitting element is not specifically limited, For example, a laser diode (LD) and a light emitting diode (LED) can be used.

One embodiment of the electronic device disclosed in this specification may further include a photothermal conversion unit. The photothermal conversion unit absorbs light from the light emitting element and converts it into heat. The photothermal conversion unit is configured to transfer heat to the channel unit. The material of the photothermal conversion part is not particularly limited as long as it can absorb light from the light emitting element and convert it into heat. However, it is desirable that the material of the photothermal conversion part has a characteristic of rapidly transferring the generated heat to the channel part, and therefore it is desirable to have a high thermal conductivity. For example, aluminum nitride (AlN), silicon oxide (SiO ₂ ), or diamond can be used as the material of the photothermal conversion section. When such a photothermal conversion unit is provided, light from the light emitting element can be efficiently converted into heat, and the temperature of the channel unit can be increased.

  One embodiment of the electronic device disclosed herein may further include a cooler that cools the channel portion. The cooler should just cool a channel part, and the kind is not specifically limited. For example, the cooler may have water-cooled or air-cooled fins or may have a heat pipe. Alternatively, the cooler may be a casing that fills the periphery of the channel portion with helium gas (He). If such a cooler is provided, the temperature of the channel portion can be lowered. For this reason, the phase change material contained in the channel part can effectively phase change between the metal phase and the insulator phase by the temperature rise by the temperature rise generation part and the temperature drop by the cooler.

  More specifically, one embodiment of the electronic device disclosed in the present specification may include a substrate, a channel unit, a first electrode, a second electrode, and a temperature increase generation unit. The substrate may be any material as long as it supports the channel portion, and the material is not particularly limited. However, the substrate is preferably made of an insulating material in order to suppress leakage of current flowing through the channel portion. The channel portion is provided on the substrate, and includes a phase change material that undergoes a phase transition between the metal phase and the insulator phase due to a temperature change. The channel part may be provided so as to be in contact with the upper surface of the substrate, or may be provided on the substrate via another member. The first electrode is provided on the channel portion and is electrically connected to a part of the upper surface of the channel portion. The second electrode is provided on the channel portion and is electrically connected to another part of the upper surface of the channel portion. That is, each of the first electrode and the second electrode is in contact with a different position on the upper surface of the channel portion. The temperature increase generation unit is configured to increase the temperature of the channel unit.

  The temperature rise generation unit may include a light emitting element. In this case, the light emitting element is desirably arranged on the upper surface side of the channel portion. The light emitting element may be disposed so as to face the upper surface of the channel portion with a space in between. Alternatively, the light emitting element may be fixed in contact with the upper surface of the channel part, or may be fixed on the channel part via another member.

  One embodiment of the electronic device disclosed in this specification may further include a photothermal conversion unit. The photothermal conversion unit absorbs light from the light emitting element and converts it into heat. The photothermal conversion part may be provided on the channel part, may be provided below the channel part, or may be provided below the substrate. However, the photothermal conversion unit is preferably provided on the channel unit. In this case, the photothermal conversion part may be provided so as to be in contact with the upper surface of the channel part, or may be provided on the channel part via another member. When such a photothermal conversion unit is provided, the channel unit and the photothermal conversion unit are close to each other, so that the temperature of the channel unit can be rapidly increased. For this reason, the electronic device of this embodiment can have high-speed responsiveness. Furthermore, when such a photothermal conversion part is provided, the temperature of a channel part can be raised uniformly.

  One embodiment of the electronic device disclosed herein may further comprise a cooler. The cooler is provided under the substrate and cools the channel portion. When such a cooler is provided, the heat of the channel part is radiated to the cooler via the substrate. Thereby, the temperature of the channel part can be lowered. For this reason, the phase change material contained in the channel part can effectively phase change between the metal phase and the insulator phase due to the temperature rise due to the temperature rise generation part temperature and the temperature drop due to the cooler.

  Hereinafter, the electronic device of each embodiment will be described with reference to the drawings. In addition, about the component which is substantially common, a common code | symbol is attached | subjected and repeated description may be abbreviate | omitted.

  As shown in FIG. 1, the electronic device 1 includes a cooler 10, a substrate 20, a channel part 30, a drain electrode 42, a source electrode 44, a photothermal conversion part 50, and a light emitting element 60.

  The cooler 10 is a water-cooled heat sink having fins. The cooler 10 radiates the heat of the channel part 30 to the outside and cools the channel part 30. The cooling target temperature of the cooler 10 is set to a value lower than the phase transition temperature of the phase transition material of the channel part 30 as described later.

The substrate 20 is made of an insulating material. As will be described later, the substrate 20 is used as a base when the channel portion 30 is formed. Therefore, the substrate 20 is desirably a material that can form the channel portion 30, and is desirably a material having a lattice constant close to the lattice constant of the crystal structure of the channel portion 30. In this example, aluminum oxide (Al ₂ O ₃ ) is used as the material of the substrate 20.

The channel unit 30 is provided on the substrate 20 and is in contact with the upper surface of the substrate 20. The channel part 30 is comprised with the phase transition material which changes a metal phase and an insulator phase by temperature change. In this example, the channel part 30 is made of a transition metal oxide Mott insulator. Specifically, vanadium dioxide (VO ₂ ) is used as the material of the channel portion 30. The transition metal oxide Mott insulator can reversibly transition between the metal phase and the insulator phase at the phase transition temperature. Vanadium dioxide has a phase transition temperature of about 340 K, and is an insulator phase at a temperature lower than the phase transition temperature, and is a metal phase at a temperature higher than the phase transition temperature. The phase transition temperature of vanadium dioxide can be set to a desired value by controlling oxygen defects and impurities.

  The drain electrode 42 is provided on the channel part 30 and is in ohmic contact with a part of the upper surface of the channel part 30. In this example, the material of the drain electrode 42 is titanium or chromium. The surface of the drain electrode 42 may be coated with gold for preventing oxidation.

  The source electrode 44 is provided on the channel portion 30, is disposed away from the drain electrode 42, and is in ohmic contact with a part of the upper surface of the channel portion 30. In this example, the source electrode 44 is made of titanium or chromium. The surface of the source electrode 44 may be coated with gold for preventing oxidation.

  The photothermal conversion unit 50 is provided on the channel unit 30 and is in contact with the upper surface of the channel unit 30. The photothermal conversion unit 50 is provided so as to cover the entire range of the upper surface of the channel unit 30 existing between the drain electrode 42 and the source electrode 44. The photothermal conversion unit 50 absorbs light from the light emitting element 60 and converts it into heat. For this reason, a material that can absorb the light emitted from the light emitting element 60 is adopted as the material of the photothermal conversion unit 50. In this example, aluminum nitride (AlN) is used as the material of the photothermal conversion unit 50. In addition, aluminum nitride has a characteristic that it has a high thermal conductivity and is an insulator. For this reason, the photothermal conversion unit 50 can efficiently transfer heat to the channel unit 30 and can suppress a short circuit between the drain electrode 42 and the source electrode 44.

  The light emitting element 60 is disposed above the photothermal conversion unit 50 with a space therebetween, and faces the upper surface of the photothermal conversion unit 50. The light emitting element 60 is a laser diode, and is configured so that laser light is incident on the photothermal conversion unit 50. In this example, the light emitting element 60 is a laser diode that emits infrared light.

  Next, the operation of the electronic device 1 will be described. The electronic device 1 is used with a high positive voltage (for example, 600 V) applied to the drain electrode 42 and a ground voltage applied to the source electrode 44. When the light emitting element 60 emits laser light and the laser light enters the photothermal conversion unit 50, the photothermal conversion unit 50 absorbs the laser light and generates heat. The heat generated in the photothermal conversion unit 50 is transferred to the channel unit 30. As described above, the channel portion 30 has the property of a metal phase when the temperature is equal to or higher than the phase transition temperature. For this reason, when the light emitting element 60 emits laser light and the temperature of the channel portion 30 becomes equal to or higher than the phase transition temperature, the channel portion 30 is in a metal phase, and a current flows between the drain electrode 42 and the source electrode 44. . As described above, when the light emitting element 60 emits laser light and the temperature of the channel portion 30 becomes equal to or higher than the phase transition temperature, the electronic device 1 is in the on state.

  Next, when the light emitting element 60 stops emitting laser light, the temperature of the channel portion 30 decreases due to the cooling effect of the cooler 10. Since the cooling target temperature of the cooler 10 is set to a temperature lower than the phase transition temperature, the temperature of the channel part 30 becomes lower than the phase transition temperature. When the temperature of the channel part 30 becomes lower than the phase transition temperature, the channel part 30 has the property of an insulator phase. For this reason, when the light emitting element 60 stops emitting the laser light and the temperature of the channel part 30 becomes lower than the phase transition temperature, the channel part 30 is in an insulator phase, and between the drain electrode 42 and the source electrode 44. Current does not flow. Thus, when the light emitting element 60 stops emitting the laser light and the temperature of the channel portion 30 becomes lower than the phase transition temperature, the electronic device 1 is in the off state.

  As described above, in the electronic device 1, the temperature of the channel part 30 is controlled based on the laser light of the light emitting element 60, and thereby the phase transition between the metal phase and the insulator phase is controlled in the channel part 30. The As a result, the electronic device 1 can operate as a transistor that is switched on and off based on the laser light of the light emitting element 60.

Hereinafter, the characteristics of the electronic device 1 will be summarized.
(1) The electronic device 1 is in an off state when the light emitting element 60 is not emitting laser light. For this reason, the electronic device 1 can operate as normally-off.
(2) The breakdown voltage of the channel part 30 depends on the thickness and distance of the channel part 30 (the distance between the drain electrode 42 and the source electrode 44). The breakdown voltage of the channel part 30 does not depend on the impurity concentration as in the channel part of the conventional semiconductor device. For this reason, the electronic device 1 can have a high breakdown voltage and a low on-resistance characteristic.
(3) The channel portion 30 undergoes a phase transition between the metal phase and the insulator phase due to a temperature change. That is, since the electronic device 1 does not use the field effect, it is resistant to external voltage noise. The electronic device 1 can have high reliability against external noise.
(4) Since the photothermal conversion unit 50 is provided so as to cover the upper surface of the channel unit 30, the adsorption of moisture in the atmosphere on the upper surface of the channel unit 30 is suppressed, and the drain electrode 42 and the source electrode 44 Short circuit between them is suppressed. The photothermal conversion unit 50 can also function as a protective film that protects the channel unit 30.

Next, a method for manufacturing the electronic device 1 will be described. First, as shown in FIG. 2, a substrate 20 is prepared. As the substrate 20, a single crystal substrate of aluminum oxide (Al ₂ O ₃ ) is used.

  Next, as shown in FIG. 3, a channel portion 30 is formed on the upper surface of the substrate 20. As a film formation method, a PLD method, a sputtering method, a CVD method, an ALD method, an MBE method, or a spin coating method can be used.

  Next, as illustrated in FIG. 4, the photothermal conversion unit 50 is formed on the upper surface of the channel unit 30. As a film formation method, a PLD method, a sputtering method, a CVD method, an ALD method, an MBE method, or a spin coating method can be used.

  Next, as shown in FIG. 5, a part of the photothermal conversion unit 50 is removed, and the upper surface of the channel unit 30 is exposed. A part of the photothermal conversion unit 50 can be removed using a dry etching method.

  Next, as shown in FIG. 6, the drain electrode 42 and the source electrode 44 are formed on a part of the upper surface of the channel portion 30. As a forming method, after a metal film is coated on the upper surface of the channel portion 30 by an EB vapor deposition method or a sputtering method, patterning can be performed by a lift-off method or a dry etching method.

  Next, as shown in FIG. 7, the cooler 10 prepared in advance is attached to the lower surface of the substrate 20. Finally, the light emitting element 60 is attached above the photothermal conversion unit 50. Thereby, the electronic device 1 is completed.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

10: Cooler 20: Substrate 30: Channel part 42: Drain electrode 44: Source electrode 50: Photothermal conversion part 60: Light emitting element

Claims (5)

A channel portion including a phase change material that causes a phase change between a metal phase and an insulator phase due to a temperature change;
Configured to increase the temperature of the channel portion, a temperature increase generation unit having a light emitting element ;
A light-to-heat converter that absorbs light from the light-emitting element and converts it into heat, and
The photothermal conversion unit is an electronic device configured to transfer heat to the channel unit . A channel portion including a phase change material that causes a phase change between a metal phase and an insulator phase due to a temperature change;
A temperature rise generator configured to increase the temperature of the channel portion;
Electronic device and a cooler for cooling the channel portion. A substrate,
A channel portion that is provided on the substrate and includes a phase change material that undergoes a phase transition between a metal phase and an insulator phase due to a temperature change;
A first electrode provided on the channel portion and electrically connected to a part of the upper surface of the channel portion;
A second electrode provided on the channel portion and electrically connected to another part of the upper surface of the channel portion;
A temperature rise generator configured to increase the temperature of the channel portion, and having a light emitting element disposed on an upper surface side of the channel portion ;
An electronic device comprising: a photothermal conversion unit provided on the channel unit and configured to absorb light from the light emitting element and convert it into heat . A substrate,
A channel portion that is provided on the substrate and includes a phase change material that undergoes a phase transition between a metal phase and an insulator phase due to a temperature change;
A first electrode provided on the channel portion and electrically connected to a part of the upper surface of the channel portion;
A second electrode provided on the channel portion and electrically connected to another part of the upper surface of the channel portion;
A temperature rise generator configured to increase the temperature of the channel portion;
It provided under the substrate, and a cooler for cooling the channel unit comprises an electronic device. The electronic device according to claim 1 , wherein the phase change material is an oxide containing a d-block transition element.

Images