JP3705099B2 - Device having piezoelectric element and method for manufacturing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a device having a piezoelectric element and a manufacturing method thereof.
[0002]
[Background]
At present, various apparatuses using the piezoelectric phenomenon of piezoelectric elements have been proposed. The piezoelectric element has a layer structure of a lower electrode, a piezoelectric body portion, and an upper electrode. Piezoelectric elements are applied to, for example, ink jet printers and various sensors.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide an apparatus having a piezoelectric element and a method for manufacturing the same, in which deterioration of the characteristics of the piezoelectric element is suppressed.
[0004]
[Means for Solving the Problems]
(Apparatus having a piezoelectric element)
An apparatus having the piezoelectric element of the present invention includes:
Including a piezoelectric element provided on a substrate;
A barrier layer covering at least a part of the piezoelectric element is provided.
[0005]
Here, the “barrier layer” refers to a layer for protecting the piezoelectric element. Further, “covering the piezoelectric element” includes a mode in which the piezoelectric element is covered in contact with the piezoelectric element and a mode in which a predetermined layer is interposed to cover the piezoelectric element. These are the same in the following.
[0006]
In the present invention, a barrier layer covering at least a part of the piezoelectric element is provided. For this reason, the piezoelectric element is protected by the barrier layer. As a result, according to the present invention, it is possible to suppress the deterioration of the characteristics of the piezoelectric element due to the external action.
[0007]
The barrier layer can contain TaO _x as a main component. When the main component of the barrier layer is TaO _X, it is possible to easily etch the barrier layer. Therefore, it is suitable for high integration that requires fine processing. Furthermore, when the main component of the barrier layer is TaO _x , hydrogen can be blocked and reduction of the piezoelectric element can be suppressed. Further, the barrier layer may be composed of only TaO _X.
[0008]
When the barrier layer is mainly composed of TaO _x , the barrier layer preferably contains at least one selected from AlO _x , TiO _x , ZrO _x, and HfO _x .
[0009]
In the above metal oxide, “x” is a positive number. In general, an oxide does not have a complete stoichiometric composition, and oxygen deficiency is generated. Note that “x” may be the same numerical value in different types of metal oxides, or may be a different numerical value. These are the same in the following.
[0010]
When the barrier layer contains at least one selected from AlO _x , TiO _x , ZrO _x, and HfO _x , it is possible to suppress generation of oxygen vacancies in TaO _x due to hydrogen. As a result, by including the metal oxide, it is possible to suppress reduction of TaO _x by hydrogen. Accordingly, the ability of the barrier layer to block hydrogen can be improved.
[0011]
In the barrier layer, the ratio of the total number of atoms of Al, Ti, Zr and Hf to the number of Ta atoms (total number of atoms of Al, Ti, Zr and Hf / number of Ta atoms) is 0.05 to 0.20.
[0012]
The barrier layer may be provided only on the piezoelectric element. The barrier layer may be further provided on the side of the piezoelectric element.
[0013]
The piezoelectric element can function as an actuator. The piezoelectric element can include a first electrode, a piezoelectric body portion, and a second electrode.
[0014]
A through hole may be provided in the base under the piezoelectric element.
[0015]
A semiconductor element for controlling or driving the piezoelectric element may be provided on the base.
[0016]
(Method for manufacturing a device having a piezoelectric element)
(A) A method for manufacturing a device having the first piezoelectric element of the present invention is as follows:
(A) forming a piezoelectric element on the substrate; and (b) forming a barrier layer covering at least a part of the piezoelectric element.
[0017]
According to the method for manufacturing a device having a piezoelectric element of the present invention, the method includes the step (b) of forming a barrier layer. For this reason, after the step (b), the piezoelectric element is protected by the barrier layer. As a result, a device having a piezoelectric element in which deterioration of characteristics is suppressed can be manufactured.
[0018]
(B) A method of manufacturing a device having the second piezoelectric element of the present invention is as follows:
(H) forming a first electrode on the substrate;
(I) forming a piezoelectric film on the first electrode;
(J) forming a second electrode on the piezoelectric film;
(K) forming a barrier layer on the second electrode;
(L) including a step of selectively removing the barrier layer, the second electrode, the piezoelectric film, and the first electrode to form a piezoelectric element.
[0019]
In the method for manufacturing a device having the second piezoelectric element of the present invention, a barrier layer is formed on the second electrode in the step (k). For this reason, there can exist an effect similar to the manufacturing method of the apparatus which has the 1st piezoelectric element of this invention.
[0020]
According to the present invention, in step (l), the barrier layer functions to protect the piezoelectric element.
[0021]
The barrier layer can take the form described in the section of the device having a piezoelectric element. The barrier layer can be formed by sputtering, CVD or laser ablation. According to these methods, it is easy to form a barrier layer having a dense film. Moreover, these methods have good coverage.
[0022]
Moreover, the process (s) which forms a through-hole in the base | substrate in the formation area of the said piezoelectric element can be included.
[0023]
Moreover, the process (t) of forming the semiconductor element for controlling or driving a piezoelectric element on the said base | substrate can be included.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the present invention will be described with reference to the drawings.
[0025]
[Apparatus having a piezoelectric element]
Hereinafter, an apparatus having a piezoelectric element according to an embodiment will be described. FIG. 1 is a cross-sectional view schematically showing an apparatus having a piezoelectric element according to an embodiment.
[0026]
The surface region of the semiconductor substrate 10 has a piezoelectric element region A100 and a semiconductor element region A200.
[0027]
The piezoelectric element 100 is formed on the semiconductor substrate 10 in the piezoelectric element region A100. The piezoelectric element 100 has a structure in which a lower electrode 102, a piezoelectric body portion 104, and an upper electrode 106 are laminated. The lower electrode 102 also functions as a vibrating body. A through hole 12 is formed in the semiconductor substrate 10 below the piezoelectric element 100.
[0028]
A barrier layer 130 is formed on the upper electrode 104. The barrier layer 130 has a function of protecting the piezoelectric element 100. Specifically, the barrier layer 130 has a function of protecting the piezoelectric element 100 from physical or chemical action.
[0029]
A semiconductor element (for example, a field effect transistor) 200 for controlling or driving the piezoelectric element 100 is formed in the semiconductor element region A200. A silicon nitride film 210 is formed on the semiconductor element region A200. The silicon nitride film 210 has a function of protecting the semiconductor element 200. Although the semiconductor element region A200 has been briefly described here, generally, a wiring or an interlayer insulating film is formed on the semiconductor element 200.
[0030]
Hereinafter, a specific configuration of the barrier layer 130 will be described. Barrier layer 130 may be made of a material mainly composed of TaO _X. Since the barrier layer 130 is mainly composed of TaO _x , there is an advantage that the barrier layer 130 can be easily etched. Therefore, it is suitable for high integration that requires fine processing. Further, since the barrier layer 130 is mainly made of TaO _x , the barrier layer 130 has a function of blocking hydrogen and preventing the piezoelectric body portion 104 from coming into contact with hydrogen. That is, the barrier layer 130 has a function of preventing the piezoelectric body portion 104 from being reduced by hydrogen.
[0031]
When the barrier layer 130 is made of a material mainly composed of TaO _x , the barrier layer 130 preferably contains at least one selected from AlO _x , TiO _x , ZrO _x, and HfO _x . By adding such a metal oxide, it is possible to suppress the occurrence of oxygen vacancies in TaO _x . Therefore, in the step of the hydrogen after the formation of the barrier layer 130 occurs, TaO _X is is suppressed from being reduced. Therefore, the barrier layer 130 has a higher ability to block hydrogen than the case where the barrier layer 130 is made of only TaO _x .
[0032]
TiO _x , ZrO _x, and HfO _x have the effect of improving the adhesion of the barrier layer 130 in addition to the effect of suppressing the reduction of TaO _x . In the barrier layer 130, the ratio of the total number of atoms of Al, Ti, Zr and Hf to the number of Ta atoms (total number of atoms of Al, Ti, Zr and Hf / number of Ta atoms) is preferably 0.05. It is -0.20, More preferably, it is 0.05-0.10. When the ratio is less than 0.05 tends to hardly exhibit the effect of suppressing the oxygen deficiency of TaO _X occurs. On the other hand, when the ratio exceeds 0.20, the barrier layer 130 tends to hardly exhibit the function of blocking hydrogen.
[0033]
(Operation)
Hereinafter, the operation of the apparatus having the piezoelectric element will be described.
[0034]
When a voltage is applied to the piezoelectric element 100, the piezoelectric body portion 104 is distorted by the piezoelectric effect. When the piezoelectric body portion 104 is distorted, the lower electrode 102 is bent. That is, the piezoelectric element 100 can function as an actuator.
[0035]
The apparatus having the piezoelectric element can function as an ink jet printer, for example. Specifically, ink can be stored in the through-hole 12 and a voltage can be applied to the piezoelectric element 100 to bend the lower electrode 110 and eject the ink.
[0036]
[Method of Manufacturing Device Having Piezoelectric Element]
Hereinafter, a method for manufacturing a device having a piezoelectric element will be described. 2 and 3 are cross-sectional views schematically showing a manufacturing process of a device having a piezoelectric element.
[0037]
First, as shown in FIG. 2A, the semiconductor element 200 is formed in the semiconductor element region A200 by a known method. Next, a silicon nitride film 210 for protecting the semiconductor element 200 is formed in the semiconductor element region A200 by CVD. The thickness of the silicon nitride film 210 is, for example, 100 to 800 nm. Next, the silicon nitride film 210 in the piezoelectric element region A100 is selectively etched using a lithography technique.
[0038]
Next, as shown in FIG. 2B, a first conductive layer 102 a for the lower electrode 102 is formed on the semiconductor substrate 10. As the material of the first conductive layer 102a, may for example _{Ir, IrO y, Pt, Ru} , RuO y, SrRuO y, and the like LaSrCoO _y. The first conductive layer 102a can be formed by, for example, a CVD method or a sputtering method. In addition, when using an oxide, it is preferable that it is a composite electrode which laminated | stacked the oxide and the metal like SrRuOy / Pt, for example. The thickness of the first conductive layer 102a is, for example, 50 to 200 nm.
[0039]
Next, as shown in FIG. 3A, through holes 12 are formed in the semiconductor substrate 10 in the piezoelectric element region A100 by a known method. For example, the through hole 12 can be formed by etching from the back surface of the semiconductor substrate 10.
[0040]
Next, as shown in FIG. 3B, a piezoelectric film 104a is formed on the first conductive layer 102a. As the material of the piezoelectric film 104a, mention may be made of _{PZT (PbZr Z Ti 1-Z} O 3). Examples of the method for forming the piezoelectric film 104a include a spin coating method, a dipping method, a sputtering method, an MOCVD method, and a laser ablation method using a sol-gel material or a MOD material. The thickness of the piezoelectric film 104a is, for example, 0.5 to 5 μm.
[0041]
Next, a second conductive layer 106a for the upper electrode 106 is formed on the piezoelectric film 104a. The material and formation method of the second conductive layer 106a can be the same as those of the first conductive layer 102a. The thickness of the second conductive layer 106a is, for example, 50 to 200 nm.
[0042]
Next, the barrier layer 130 is formed over the second conductive layer 106a. Examples of the method for forming the barrier layer 130 include a sputtering method, a CVD method, and a laser ablation method. The thickness of the barrier layer 130 is, for example, 10 to 100 nm, preferably 20 to 50 nm.
[0043]
If the barrier layer 130 is too thin, the barrier effect is small, and if it is too thick, the operation of the piezoelectric element 100, for example, deflection, is hindered.
[0044]
Next, as shown in FIG. 1, the barrier layer 130, the second conductive layer 106a, the piezoelectric film 104a, and the first conductive layer 102a are selectively etched using a lithography technique. Thus, the piezoelectric element 100 including the upper electrode 106, the piezoelectric body portion 104, and the lower electrode 102 is formed. During this etching, the barrier layer 130 functions to prevent the piezoelectric element 100 from being damaged. The silicon nitride film 210 functions to prevent the semiconductor element 200 from being damaged by etching.
[0045]
The through hole 12 may be formed after the piezoelectric element 100 is formed.
[0046]
(Function and effect)
Hereinafter, effects of the manufacturing process of the apparatus having the piezoelectric element according to the embodiment will be described.
[0047]
A barrier layer 130 is formed on the piezoelectric element 100. For this reason, the piezoelectric element can be protected from physical or chemical action in the process after the barrier layer 130 is formed. As a result, according to the present invention, it is possible to manufacture a device having a piezoelectric element in which deterioration of characteristics is suppressed.
[0048]
[Modification]
The present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention. The device having the piezoelectric element can be changed as follows, for example.
[0049]
As shown in FIG. 4, the barrier layer 130 may be formed not only on the piezoelectric element 100 but also on the side of the piezoelectric element 100.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing an apparatus having a piezoelectric element according to an embodiment.
FIG. 2 is a cross-sectional view schematically showing a manufacturing process of the device having the piezoelectric element according to the embodiment.
FIG. 3 is a cross-sectional view schematically showing a manufacturing process of the device having the piezoelectric element according to the embodiment.
FIG. 4 is a cross-sectional view schematically showing an apparatus having a piezoelectric element according to a modification.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Semiconductor substrate 12 Through-hole 100 Piezoelectric element 102 Lower electrode 102a First conductive layer 104 Piezoelectric part 104a Piezoelectric film 106 Lower electrode 106a Second conductive layer 130 Barrier layer 200 Semiconductor element 210 Silicon nitride film A100 Piezoelectric element region A200 Semiconductor device area

Claims (15)

Including a piezoelectric element provided on a substrate;
A barrier layer covering at least a part of the piezoelectric element is provided;
The apparatus having a piezoelectric element, wherein the barrier layer contains TaO _x as a main component and includes at least one selected from AlO _x , TiO _x , ZrO _x, and HfO _x . In claim 1,
The apparatus having a piezoelectric element, wherein in the barrier layer, a ratio of a total number of Al, Ti, Zr, and Hf atoms to the number of Ta atoms is 0.05 to 0.20. In claim 1 or 2,
The apparatus having a piezoelectric element, wherein the barrier layer is provided only on the piezoelectric element. In any one of Claims 1-3,
The device having a piezoelectric element, wherein the barrier layer is further provided on a side of the piezoelectric element. In any one of Claims 1-4,
The piezoelectric element functions as an actuator and has a piezoelectric element. In any one of Claims 1-5,
The piezoelectric element includes a first electrode, a second electrode, and a piezoelectric element having a piezoelectric body portion provided between the first electrode and the second electrode. In any one of Claims 1-6,
An apparatus having a piezoelectric element, wherein a through-hole is provided in a base under the piezoelectric element. In any one of Claims 1-7,
An apparatus having a piezoelectric element, wherein a semiconductor element for controlling or driving the piezoelectric element is provided on the substrate. (A) forming a piezoelectric element on the substrate, and (b) forming a barrier layer covering at least a part of the piezoelectric element,
The method for manufacturing a device having a piezoelectric element, wherein the barrier layer contains TaO _x as a main component and includes at least one selected from AlO _x , TiO _x , ZrO _x, and HfO _x . (H) forming a first electrode on the substrate;
(I) forming a piezoelectric film on the first electrode;
(J) forming a second electrode on the piezoelectric film;
(K) forming a barrier layer on the second electrode;
(L) selectively removing the barrier layer, the second electrode, the piezoelectric film, and the first electrode to form a piezoelectric element;
The method for manufacturing a device having a piezoelectric element, wherein the barrier layer contains TaO _x as a main component and includes at least one selected from AlO _x , TiO _x , ZrO _x, and HfO _x . In claim 9 or 10,
In the barrier layer, a method of manufacturing a device having a piezoelectric element, wherein a ratio of a total number of atoms of Al, Ti, Zr, and Hf to the number of Ta atoms is 0.05 to 0.20. In any one of Claims 9-11,
The barrier layer is formed by a sputtering method, a CVD method or a laser ablation method. In any one of Claims 9-12,
A method for manufacturing a device having a piezoelectric element, comprising a step (s) of forming a through hole in a substrate in a formation region of the piezoelectric element. In any one of Claims 9-13,
A method of manufacturing a device having a piezoelectric element, comprising a step (t) of forming a semiconductor element for controlling or driving the piezoelectric element on the substrate. In any one of Claims 9-14,
The method for manufacturing a device having a piezoelectric element, wherein the piezoelectric element functions as an actuator.

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