JP2011192923A - Thermoelectric conversion apparatus, and method of manufacturing the same - Google Patents

Abstract

The present invention provides a thermoelectric conversion device that can be remarkably miniaturized as compared with one using a bulk material and a method for manufacturing the same.
A thermoelectric conversion device is provided with a substrate and a pair of a p-type semiconductor film and an n-type semiconductor film that are provided above the substrate and have one end bonded to each other.
[Selection] Figure 1

Description

  The present invention relates to a thermoelectric conversion device and a manufacturing method thereof.

  Thermoelectric power generation converts a temperature difference, which is natural energy, into electric power. Therefore, according to thermoelectric power generation, electric power can be obtained without generating carbon dioxide. For this reason, thermoelectric power generation is expected as a next-generation clean power generation technology. Conventionally, a thermoelectric conversion device used for thermoelectric power generation is configured by connecting a plurality of bulk materials produced by sintering and cutting a thermoelectric material.

  On the other hand, in recent years, there is an increasing demand for reduction in manufacturing cost and miniaturization of thermoelectric conversion devices.

  However, in the conventional thermoelectric conversion device using the bulk material as described above, it is difficult to further reduce the manufacturing cost and make it finer.

Japanese Patent Laid-Open No. 10-228035 JP 2000-299457 A JP 2001-189497 A Japanese Patent Application Laid-Open No. 2004-235639 JP 2006-186255 A

  The objective of this invention is providing the thermoelectric conversion apparatus which can be refined | miniaturized remarkably compared with what used the bulk material, and its manufacturing method.

  One embodiment of a thermoelectric conversion device includes a substrate and a pair of a p-type semiconductor film and an n-type semiconductor film that are provided above the substrate and bonded to each other at one end.

  According to the above-described thermoelectric conversion device or the like, the pair of the p-type semiconductor film and the n-type semiconductor film generates electric power, so that it can be significantly miniaturized.

It is a figure which shows the structure of the thermoelectric conversion apparatus which concerns on 1st Embodiment. It is a schematic diagram which shows the usage example of a thermoelectric conversion apparatus. It is a figure which shows the structure of the thermoelectric conversion apparatus which concerns on 2nd Embodiment. It is a figure which shows the manufacturing method of the thermoelectric conversion apparatus which concerns on 2nd Embodiment. It is a figure which shows the manufacturing method of a thermoelectric conversion apparatus following FIG. 4A. It is a figure which shows the manufacturing method of a thermoelectric conversion apparatus following FIG. 4B. It is a figure which shows the manufacturing method of a thermoelectric conversion apparatus following FIG. 4C. It is a figure which shows the manufacturing method of a thermoelectric conversion apparatus following FIG. 4D. It is a figure which shows the structure of the thermoelectric conversion apparatus which concerns on 3rd Embodiment. It is a schematic diagram which shows the other usage example of a thermoelectric conversion apparatus.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings.

(First embodiment)
First, the first embodiment will be described. FIG. 1 is a diagram illustrating a structure of a thermoelectric conversion device (thermoelectric conversion module) according to the first embodiment. 1A is a top view, and FIGS. 1B and 1C are cross-sectional views taken along the line II in FIG. 1A, respectively, along the line II-II. FIG.

  As shown in FIG. 1, in the thermoelectric conversion device 11 according to the first embodiment, a substrate 1 is partitioned into a high temperature region 1a and a low temperature region 1b, and a p-type semiconductor extending over the substrate 1 over the high temperature region 1a and the low temperature region 1b. A film 2 and an n-type semiconductor film 3 are formed. The p-type semiconductor film 2 and the n-type semiconductor film 3 are joined to each other in the high temperature region 1a and insulated from each other in the low temperature region 1b. That is, the pn junction part of the p-type semiconductor film 2 and the n-type semiconductor film 3 exists only in the high temperature region 1a. A positive wiring is connected to the p-type semiconductor film 2, and a negative wiring is connected to the n-type semiconductor film 3. At least the surface of the substrate 1 is insulative, and current can flow between the p-type semiconductor film 2 and the n-type semiconductor film 3 only through these pn junctions.

  When the temperature of the high temperature region 1a of the thermoelectric conversion device 11 is higher than the temperature of the low temperature region 1b, electrons move from the high temperature region 1a toward the low temperature region 1b in the n-type semiconductor film 3, and the p-type semiconductor In the film 2, holes move from the high temperature region 1a toward the low temperature region 1b. That is, current tends to flow from the n-type semiconductor film 3 toward the p-type semiconductor film 2 in the high temperature region 1a. Accordingly, when an external resistor R is connected between the positive electrode and the negative electrode, a current flows from the positive electrode to the negative electrode via the external resistor R.

  In such a thermoelectric conversion device 11, since a bulk material is not used and only a semiconductor film is formed on the substrate 1, miniaturization is easy. Therefore, it can be used for various regions, and can also be used for narrow regions where a thermoelectric conversion device using a bulk material cannot be used. For example, it is possible to generate electricity using human body temperature, and this power can be applied to medical treatment. Furthermore, the formation of the semiconductor film is extremely low cost compared to the production and connection of bulk materials.

  FIG. 2 is a schematic diagram illustrating a usage example of the thermoelectric conversion device 11. As shown in FIG. 2, the thermoelectric conversion device 11 is attached to the pipe 12 such that the high temperature region 1 a side is in contact with the outer surface of the pipe 12 that is at a high temperature and the low temperature region 1 b side is in contact with the outside air. In this usage example, electric power based on the difference between the temperature (high temperature) of the pipe 12 and the outside air temperature (low temperature) is generated.

(Second Embodiment)
Next, a second embodiment will be described. FIG. 3 is a diagram illustrating a structure of a thermoelectric conversion device (thermoelectric conversion module) according to the second embodiment. 3A is a top view, and FIGS. 3B and 3C are cross-sectional views taken along line II and II-II in FIG. 3A, respectively. FIG.

  As shown in FIG. 3, in the thermoelectric conversion device 30 according to the second embodiment, a substrate 21 is partitioned into a high temperature region 21a and a low temperature region 21b, and a p-type semiconductor over the substrate 21 over the high temperature region 21a and the low temperature region 21b. The films 22-1, 22-2, and 22-3 are formed to be separated from each other. Further, on the substrate 21, an n-type semiconductor film 23-1, which is in contact with the p-type semiconductor film 22-1 in the high temperature region 21a, and is in contact with the p-type semiconductor film 22-2 in the low temperature region 21b, and p in the high temperature region 21a. N-type semiconductor film 22-2 that contacts the p-type semiconductor film 22-2, contacts the p-type semiconductor film 22-3 in the low-temperature region 21b, and n-type semiconductor that contacts the p-type semiconductor film 22-3 in the high-temperature region 21a A film 23-3 is also formed. A positive electrode wiring is connected to the p-type semiconductor film 22-1 in the low temperature region 21b. The n-type semiconductor film 23-3 extends to the low temperature region 21b, and a negative electrode wiring is connected to the n-type semiconductor film 23-3 in the low temperature region 21b.

  Furthermore, in the present embodiment, the conductive film 24-1 is formed between the substrate 21 and the portion where the p-type semiconductor film 22-1 and the n-type semiconductor film 23-1 are in contact with each other. In addition, a conductive film 24-2 is formed between a portion where the p-type semiconductor film 22-2 and the n-type semiconductor film 23-2 are in contact with the substrate 21, and the p-type semiconductor film 22-3 and the n-type semiconductor film are formed. A conductive film 24-3 is formed between the portion in contact with the substrate 23-3 and the substrate 21. That is, the conductive films 24-1 to 24-3 are in contact with the pn junction in the high temperature region 21a. Further, a protective film 29 is formed to cover the p-type semiconductor films 22-1 to 22-3, the n-type semiconductor films 23-1 to 23-3, and the conductive films 24-1 to 24-3. A positive wiring is connected to the p-type semiconductor film 22-1 and a negative wiring is connected to the n-type semiconductor film 23-3. At least the surface of the substrate 21 is insulative, and between the p-type semiconductor films 22-1 to 22-3 and the n-type semiconductor films 23-1 to 23-3, these pn junctions or conductive films 24-1 Current can only flow through 24-3.

  When the temperature of the high temperature region 21a of the thermoelectric conversion device 30 is higher than the temperature of the low temperature region 21b, electrons move from the high temperature region 21a toward the low temperature region 21b in the n-type semiconductor films 23-1 to 23-3. In the p-type semiconductor films 22-1 to 22-3, holes move from the high temperature region 21a toward the low temperature region 21b. That is, in the high temperature region 21a, current tends to flow from the n-type semiconductor film to the p-type semiconductor film across the pn junction, and in the low-temperature region 21b, the p-type semiconductor film transitions from the p-type semiconductor film to the n-type semiconductor film. A current is going to flow in the direction. Therefore, when an external resistor or the like is connected between the positive electrode and the negative electrode, a current flows from the positive electrode to the negative electrode via the external resistor or the like.

  In the present embodiment, since the conductive films 24-1 to 24-3 are in contact with the pn junction in the high temperature region 21a, the internal structure is compared with the case where the conductive films 24-1 to 24-3 are not provided. Resistance is reduced. Even if the conductive film is in contact with the pn junction in the low temperature region 21b, the internal resistance is not reduced. This is because current tends to flow from the n-type semiconductor film to the p-type semiconductor film in the high-temperature region 21a, and thus the resistance of this portion is large, whereas in the low-temperature region 21b, the p-type semiconductor film is changed to the n-type semiconductor film. This is because the resistance of this portion is small because current tends to flow toward.

  Next, a method for manufacturing the thermoelectric conversion device 30 according to the second embodiment will be described. 4A to 4E are views showing a method of manufacturing the thermoelectric conversion device 30 according to the second embodiment in the order of steps. 4A (a) to 4E (a) are top views, and FIGS. 4A (b) to 4E (b) and FIGS. 4A (c) to 4E (c) are respectively shown in FIG. 4A (a). FIG. 4E is a cross-sectional view taken along line II and a cross-sectional view taken along line II-II in FIG.

  First, as shown in FIG. 4A, conductive films 24-1 to 24-3 are formed on the substrate 1. As the substrate 1, for example, a silicon substrate having a silicon oxide film formed on the surface is used. As the conductive films 24-1 to 24-3, for example, a titanium film having a thickness of 900 nm is formed. The conductive films 24-1 to 24-3 are formed through, for example, film formation of a material, formation of a resist pattern by photolithography, etching, and the like.

  Next, as illustrated in FIG. 4B, the planar shapes are p-type semiconductor films 22-1 to 22-3 and n-type semiconductor films 23-1 to 23-3 on the substrate 1 and the conductive films 24-1 to 24-3. A semiconductor film 25 that matches the planar shape is formed. As the semiconductor film 25, for example, a polycrystalline silicon film having a thickness of 800 nm and a width of several hundred nm is formed. The formation of the semiconductor film 25 is performed, for example, through film formation of a material, formation of a resist pattern by photolithography, etching, and the like.

Thereafter, as shown in FIG. 4C, a p-type semiconductor film 26 is formed by introducing p-type impurities into the entire surface of the semiconductor film 25. As the p-type impurity, for example, boron ions are implanted with an acceleration voltage of 10 kV and a dose of 4 × 10 ¹⁵ cm ⁻² .

  Subsequently, as shown in FIG. 4D, the portions that become the p-type semiconductor films 22-1 to 22-3 of the p-type semiconductor film 26 are covered, and the portions that become the n-type semiconductor films 23-1 to 23-3 are exposed. A resist pattern 27 is formed.

Next, as shown in FIG. 4E, an n-type impurity is introduced into the portion of the p-type semiconductor film 26 exposed from the resist pattern 27 at a higher concentration than when the p-type semiconductor film 26 is formed. As an n-type impurity, for example, phosphorus ions are implanted with an acceleration voltage of 10 kV and a dose of 8 × 10 ¹⁵ cm ⁻² . As a result, n-type semiconductor films 23-1 to 23-3 are formed. Further, portions of the p-type semiconductor film 26 covered with the resist pattern 27 become p-type semiconductor films 22-1 to 22-3.

  Thereafter, the resist pattern 27 is removed, wiring is formed, and the protective film 29 is formed.

  The thermoelectric conversion device 30 can be manufactured by such a method.

  The inventor of the present application follows the method shown in FIGS. As a result, the results shown in Table 1 were obtained. In addition, Example No. For comparison with Example 1, No. 1 in which a titanium film as a conductive film was formed also at the pn junction in the low temperature region. 2 and Example No. No. 1 in which the formation of the titanium film was omitted from the high temperature region. The characteristics of 3 were also investigated. The number of p-type semiconductor films and n-type semiconductor films was 100, and the temperature difference between the high temperature region and the low temperature region was 100 ° C.

  As shown in Table 1, Example No. 2 according to the second embodiment is used. In 1 the best result was obtained.

(Third embodiment)
Next, a third embodiment will be described. FIG. 5 is a diagram illustrating a structure of a thermoelectric conversion device (thermoelectric conversion module) according to the third embodiment. 5A is a perspective view, and FIG. 5B and FIG. 5C are a cross-sectional view of a surface III and a cross-sectional view of a surface IV in FIG. 5A, respectively.

  As shown in FIG. 5, the thermoelectric conversion device 41 according to the third embodiment is provided with a thermoelectric conversion device 30 according to the second embodiment as a thermoelectric conversion sheet 31. And in the high temperature area | region 21a of the thermoelectric conversion sheet 31, the high temperature side metal film 33 is attached to the back surface of the board | substrate 21, and the low temperature side metal film | membrane 32 is attached on the protective film 29 in the low temperature area | region 21b. And the resin part 34 is provided in these circumference | surroundings.

  FIG. 6 is a schematic diagram illustrating a usage example of the thermoelectric conversion device 41. As shown in FIG. 6, the thermoelectric conversion device 41 is attached to the heating element 42 such that the high temperature region 21 a side is in contact with the outer wall surface of the heating element 42 that is at a high temperature and the low temperature region 21 b side is in contact with the outside air. In this usage example, the temperature (high temperature) of the heating element 42 is transmitted to the high temperature region 21 a via the high temperature side metal film 33, and the outside air temperature (low temperature) is transmitted to the low temperature region 21 b via the low temperature side metal film 32. . Therefore, electric power based on the temperature difference between the heating element 42 and the outside air is generated.

  According to such 3rd Embodiment, the electric power according to the temperature difference of the thickness direction of the thermoelectric conversion apparatus 41 can be obtained.

  In addition, it is preferable to use copper etc. with high heat conductivity as a material of the low temperature side metal film 32 and the high temperature side metal film 33, and it is preferable to use polyimide etc. with low heat conductivity as a material of the resin part 34. Although preferable, it is not limited to these.

  In these embodiments, the conductive film in contact with the pn junction in the high temperature region is located between the pn junction and the substrate. However, the conductive film is sandwiched between the p-type semiconductor film and n As long as it is in contact with the type semiconductor film, the conductive film may be located above or on the side of the pn junction. In addition to titanium, silver, platinum, aluminum, gold, copper, chromium, or the like can be used as a material for the conductive film.

  Moreover, as long as the wiring can withstand the temperature of the high temperature region 21a during use, the wiring may be drawn from the high temperature region 21a.

The material of the semiconductor film is not particularly limited, and SiGe, silicide (Mg ₂ Si, FeSi ₂ , CrSi ₂ ) or the like can be used in addition to silicon. The number of pn junctions is not particularly limited. Furthermore, the material of the substrate is not particularly limited, and for example, an insulating substrate may be used. In addition, if a flexible substrate is used, the application can be further expanded. However, the portion of the surface of the substrate that is in contact with the p-type semiconductor film, the n-type semiconductor film, or the conductive film is preferably insulative.

  Also, the impurity doping method is not particularly limited. For example, doping by ion shower may be performed, or a vapor phase doping method may be employed. Furthermore, after introducing the n-type impurity at a low concentration, the p-type impurity may be introduced at a high concentration.

  Hereinafter, various aspects of the present invention will be collectively described as supplementary notes.

(Appendix 1)
A substrate,
A pair of a p-type semiconductor film and an n-type semiconductor film provided on the substrate and bonded at one end to each other;
A thermoelectric conversion device comprising:

(Appendix 2)
The thermoelectric conversion device according to appendix 1, wherein the thermoelectric conversion device includes a conductive film in contact with a junction of a pair of the p-type semiconductor film and the n-type semiconductor film.

(Appendix 3)
A plurality of pairs of the p-type semiconductor film and the n-type semiconductor film;
The thermoelectric conversion device according to appendix 1 or 2, wherein the plurality of pairs are joined via the other end of the p-type semiconductor film and the other end of the n-type semiconductor film.

(Appendix 4)
The thermoelectric conversion device according to appendix 2 or 3, wherein the junction side is set to a higher temperature side than the other end of the p-type semiconductor film and the other end of the n-type semiconductor film.

(Appendix 5)
The thermoelectric conversion device according to any one of appendices 1 to 4, wherein the p-type semiconductor film and the n-type semiconductor film contain Si.

(Appendix 6)
Forming a semiconductor film above the substrate;
Introducing a p-type impurity and an n-type impurity into the semiconductor film, and forming, from the semiconductor film, a pair of a p-type semiconductor film and an n-type semiconductor film whose one ends are joined to each other;
The manufacturing method of the thermoelectric conversion apparatus characterized by having.

(Appendix 7)
The method of manufacturing a thermoelectric conversion device according to appendix 6, further comprising a step of forming a conductive film in contact with a junction of the pair of the p-type semiconductor film and the n-type semiconductor film.

(Appendix 8)
In the step of introducing p-type impurities and n-type impurities into the semiconductor film, a plurality of pairs of the p-type semiconductor film and the n-type semiconductor film are formed, and the plurality of pairs are connected to the other end of the p-type semiconductor film and the The method of manufacturing a thermoelectric conversion device according to appendix 6 or 7, wherein the n-type semiconductor film is formed so as to be bonded via the other end.

(Appendix 9)
The method of manufacturing a thermoelectric conversion device according to any one of appendices 6 to 8, wherein the semiconductor film contains Si.

1, 21: Substrate 1a, 21a: High temperature region 1b, 21b: Low temperature region 2, 222-1 to 22-3: p-type semiconductor film 3, 233-1 to 23-3: n-type semiconductor film 24-1 to 24 -3: conductive film

Claims (6)

A substrate,
A pair of a p-type semiconductor film and an n-type semiconductor film provided on the substrate and bonded at one end to each other;
A thermoelectric conversion device comprising:   2. The thermoelectric conversion device according to claim 1, further comprising a conductive film in contact with a junction of a pair of the p-type semiconductor film and the n-type semiconductor film. A plurality of pairs of the p-type semiconductor film and the n-type semiconductor film;
The thermoelectric conversion device according to claim 1 or 2, wherein the plurality of pairs are bonded to each other via the other end of the p-type semiconductor film and the other end of the n-type semiconductor film.   4. The thermoelectric conversion device according to claim 2, wherein the junction side is set to a higher temperature side than the other end of the p-type semiconductor film and the other end of the n-type semiconductor film. Forming a semiconductor film above the substrate;
Introducing a p-type impurity and an n-type impurity into the semiconductor film, and forming, from the semiconductor film, a pair of a p-type semiconductor film and an n-type semiconductor film whose one ends are joined to each other;
The manufacturing method of the thermoelectric conversion apparatus characterized by having.   In the step of introducing p-type impurities and n-type impurities into the semiconductor film, a plurality of pairs of the p-type semiconductor film and the n-type semiconductor film are formed, and the plurality of pairs are connected to the other end of the p-type semiconductor film and the 6. The method of manufacturing a thermoelectric conversion device according to claim 5, wherein the n-type semiconductor film is formed so as to be bonded through the other end of the n-type semiconductor film.

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