CN112038472A - Method for manufacturing bismuth telluride-based thin film thermoelectric module, thermoelectric module and thermoelectric generator - Google Patents

Abstract

The invention discloses a manufacturing method of a bismuth telluride based thin film thermoelectric module, the thermoelectric module and a thermoelectric generator, wherein the manufacturing method comprises the following steps: depositing a silicon dioxide film layer on the heat sink substrate; preparing a plurality of metal strips which are arranged at intervals on the silicon dioxide film layer; alternately depositing a P-type bismuth telluride-based film and an N-type bismuth telluride-based film on the upper surface of the silicon dioxide film between different metal strips to obtain a first semi-finished product; coating photoresist on the upper surface of the first semi-finished product, removing part of the photoresist on the metal strips, and alternately arranging the metal strips with the photoresist removed and the metal strips without the photoresist removed; depositing a metal layer on the metal belt with the photoresist removed to obtain a second semi-finished product; coating photoresist on the upper surface of the second semi-finished product, and removing the photoresist on the metal layer; and depositing a heat conduction insulating layer on the metal layer with the photoresist removed. The invention realizes the expandability of the planar bismuth telluride based thin film thermoelectric generator by utilizing the MEMS micromachining technology and the thin film deposition technology.

Description

Method for manufacturing bismuth telluride-based thin film thermoelectric module, thermoelectric module and thermoelectric generator

technical field

The invention relates to the field of thermoelectric material power generation, in particular to a manufacturing method of a planar bismuth telluride-based thin film thermoelectric module, a thermoelectric module and a thermoelectric generator.

Background technique

Ambient energy harvesting technology is expected to enable the application of portable, wearable and distributed sensor network systems in the IoT society. Available energy sources include sunlight, indoor lighting, radio waves, mechanical vibration and heat. Efficient utilization of thermal energy has been a long-awaited issue, and thermoelectric (TE) generators that utilize the Seebeck effect to convert temperature differences into electrical energy have also received extensive attention. The energy conversion efficiency generated by TE mainly depends on the advantages of the TE material, ZT=S ² σT k ^-1 , where S represents the Seebeck coefficient, σ and k represent the electrical and thermal conductivity, respectively, and T represents the average temperature of the cold and heat sources. Increasing ZT can improve conversion efficiency, but the correlation between S, σ and k prevents this. Only a few materials, such as bismuth-tellurium and lead-tellurium, are known to achieve high conversion efficiencies.

The fundamental understanding of electricity and heat transport has improved over the past two decades. With the help of micro-nanotechnology, this understanding has led to substantial enhancements in the performance of TE materials. Bismuth telluride-based low-dimensional materials have emerged as promising TE candidates due to maintaining the properties of low thermal conductivity and high electrical conductivity. Bismuth telluride-based TE generators that are highly compatible with MEMS processes and low contamination (unlike Pb) are also increasingly being fabricated and reported.

Thermoelectric (TE) phenomenon is also called thermoelectric phenomenon. In 1822, Thomas Seebeck discovered the thermoelectromotive force effect (the principle of TE material power generation); in 1834, Jean Peltier discovered the cooling effect at the junction interface of two conductors of different materials in the current loop (the principle of TE material refrigeration). Some good semiconducting TE materials were discovered in the 1950s. Materials with ZT ≥ 0.5 are usually referred to as TE materials. The larger the ZT, the higher the efficiency of the TE device. In order to overcome the obstacle of the lack of TE materials with high ZT value, people turn to the structural design of natural TE materials and the development of synthetic TE materials—low-dimensional thermoelectric materials. Mesoscopic physical theoretical studies have shown that, under the same working conditions, low-dimensional thin-film structured TE materials have higher ZT values than other bulk materials.

So far, there are three types of TE materials with typical low-dimensional thin film structures: (1) Quantum-dot structures, which increase the density of states near the Fermi level by means of quantum-confinement effects, thereby increasing the The electrical conductivity of the material; (2) phonon low-pass/electron-transmitting superlattices (phonon-blocking/electron-transmitting superlattices). The lattice thermal conductivity (kL) of the material is reduced by "acoustic-mismatch". Unlike conventional TE alloy materials, materials with this type of structure usually have a significantly reduced carrier scattering rate, that is, to obtain high electrical conductivity. (3) A thin-film structure material that utilizes the thermal effects of semiconductor heterojunctions (thermionic effects in heterostructures) to improve the ZT value of the material. Hicks and Dresslhaus proposed that quantum well superlattices can greatly improve the ZT value of materials, and quantum wire superlattices can bring even greater improvements.

So far, the main materials are bismuth intermetallic compounds such as bismuth telluride (Bi ₂ Te ₃ ), lead telluride (PtTe), zinc antimonide (ZnSb), germanium, iron silicide (FeSi ₂ ), etc., among which, especially Bi ₂ Te ₃ based compounds have a large ZT value at relatively low temperature, rising from room temperature to about 450K, and are currently widely used thermoelectric conversion materials. The research on new low-dimensional TE structural materials has great theoretical and application value. The discovery of high ZT value materials (ZT>4) will trigger a technological revolution in the refrigeration industry, energy industry and semiconductor microelectronics industry. Although quantum dots or superlattice materials can obtain thermoelectric materials with dimensionless figure of merit above 2, the complex process, high cost, and difficulty in mass production of such structural materials limit their application. Micro-nanostructured thermoelectric devices may be a more realistic route for the industrial application of thermoelectric materials. In the conventional structure of planar bismuth telluride-based TE generators, the bismuth telluride-based thin film is usually suspended on the cavity to cut off the bypass. Although the cavity ensures the temperature difference between the two ends of the film, its structure weakens the mechanical strength of the device and greatly increases the manufacturing cost.

SUMMARY OF THE INVENTION

In order to overcome the deficiencies of the prior art, the present invention provides a method for manufacturing a planar bismuth telluride-based thin-film thermoelectric module, a thermoelectric module and a thermoelectric generator. The technical solutions are as follows:

In one aspect, the present invention provides a method for manufacturing a planar bismuth telluride-based thin-film thermoelectric module, comprising the following steps:

S1, deposit a silicon dioxide film layer on the heat sink substrate;

S2, preparing a plurality of metal strips arranged at intervals on the silicon dioxide film layer;

S3. Alternately deposit a P-type bismuth telluride-based thin film and an N-type bismuth telluride-based thin film on the upper surface of the silicon dioxide film between different metal strips, so that P-type tellurium is deposited on one side of each metal strip A bismuthide-based film, and an N-type bismuth telluride-based film is deposited on the other side to obtain a first semi-finished product;

S4. Coat the photoresist on the upper surface of the first semi-finished product, and remove the photoresist on part of the metal strips, so that the metal strips with the photoresist removed and the metal strips without the photoresist are alternately arranged ;

S5, depositing a metal layer on the metal strip from which the photoresist is removed to obtain a second semi-finished product;

S6, coating photoresist on the upper surface of the second semi-finished product, and removing the photoresist on the metal layer deposited in step S5;

S7, depositing a thermally conductive insulating layer on the metal layer from which the photoresist was removed.

Further, after the step S7 is performed, it also includes removing the thermally conductive insulating layer deposited outside the metal layer.

Further, before step S1, the method further includes: performing micro-arc oxidation treatment on both the upper and lower surfaces of the heat sink substrate to obtain a ceramic oxide layer, and the thickness of the ceramic oxide layer is in the range of 5-15 μm.

Further, the thickness of the metal strip is 10-30 μm, the length is 15-30 mm, and the width is 0.8-1.2 μm; the P-type bismuth telluride-based thin film and the N-type bismuth telluride-based thin film The thickness range is 30-80 nm, the length range is 0.8-1.2 μm, and the width range is 0.6-0.8 μm.

Further, the thickness range of the silicon dioxide film layer deposited in the S1 step is 80-120 μm, and the amorphous silicon film is rapidly deposited by the PECVD method and then obtained by high temperature oxidation with wet oxygen; the photoresist coated in the S4 step and The thickness of the photoresist coated in step S6 is 50-100 μm; the thickness of the metal layer deposited in step S5 is 50-100 μm; the thickness of the thermally conductive insulating layer in step S7 is 50-100 μm, and the thermally conductive insulating layer has a thickness in the range of 50-100 μm. The layers are made of aluminum nitride.

In another aspect, the present invention provides a planar bismuth telluride-based thin film thermoelectric module, comprising a heat sink substrate, a silicon dioxide film layer, a plurality of first metal strips, a plurality of second metal strips, a bismuth telluride-based thin film, a photoresist and a thermally conductive insulating layer, the silicon dioxide film layer is disposed on the upper surface of the heat sink substrate, and the first metal strip and the second metal strip are alternately arranged on the silicon dioxide film The upper surface of the layer; the adjacent first metal strips and the second metal strips are connected and conducted through a bismuth telluride-based thin film deposited on the silicon dioxide film layer, and the bismuth telluride-based thin film includes P-type bismuth telluride base film and N-type bismuth telluride-based film, different types of bismuth telluride-based films are distributed on both sides of the first metal strip and the second metal strip, and the adjacent first metal strip and all One or more bismuth telluride-based thin films of the same type are distributed between the second metal strips;

The surface of the second metal strip is covered by the thermally conductive insulating layer, except that the surface covered by the thermally conductive insulating layer is covered by the photoresist, and the height of the thermally conductive insulating layer is greater than the height of the photoresist .

Further, the adjacent first metal strips and the second metal strips are arranged at equal intervals, the width of the first metal strip is the same as the width of the second metal strip, and the P-type bismuth telluride The lengths of the base film and the N-type bismuth telluride base film are both equal to the distance between the adjacent first metal strips and the second metal strips.

Further, the thickness of the second metal strip is not less than the thickness of the first metal strip, the thickness of the first metal strip is in the range of 10-30 μm, and the lengths of the first metal strip and the second metal strip are The range is 15-30mm, the width range is 0.8-1.2μm, the first metal strip and the second metal strip are made of the same or different materials, the first metal strip and the second metal strip are made of the same or different materials. Made of aluminium, gold or silver.

Further, the P-type bismuth telluride-based thin film and the N-type bismuth telluride-based thin film are alternately arranged in rows on the upper surface of the silicon dioxide film layer;

The spacing in the longitudinal direction of a plurality of the same type of bismuth telluride-based thin films between the adjacent first metal strips and the second metal strips is equal to the width of the same type of bismuth telluride-based thin films.

In yet another aspect, the present invention provides a thermoelectric generator, comprising the above-mentioned planar bismuth telluride-based thin film thermoelectric module.

The beneficial effects brought by the technical scheme provided by the invention are as follows:

a. Using MEMS micromachining technology and thin film deposition technology, planar bismuth telluride-based thin film thermoelectric modules and thermoelectric generators have good scalability;

b. The thermoelectric power density is effectively improved by shortening the length of the bismuth telluride-based-NW to the sub-micron scale;

c. It is suitable for the synthesis and preparation of planar thin-film TE generators of various material systems, with strong applicability;

d. Wide range of use, can be widely used in portable, wearable and distributed sensor network systems and other fields.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

1 is a front cross-sectional view of a planar bismuth telluride-based thin-film thermoelectric generator provided by an embodiment of the present invention;

2 is a schematic diagram of a top layer structure of a planar bismuth telluride-based thin-film thermoelectric generator provided by an embodiment of the present invention;

3 is a structural diagram of a planar bismuth telluride-based thin film thermoelectric generator unit provided by an embodiment of the present invention.

Wherein, the reference numerals include: 1- heat sink substrate, 2- silicon dioxide film layer, 3- first metal strip, 4- second metal strip, 5-P-type bismuth telluride-based thin film, 6-N-type tellurium Bismuth-based thin film, 7- thermally conductive insulating layer, 8- photoresist.

Detailed ways

In order for those skilled in the art to better understand the solutions of the present invention, and to more clearly understand the purpose, technical solutions and advantages of the present invention, the technical solutions in the embodiments of the present invention will be clarified below in conjunction with specific embodiments and with reference to the accompanying drawings. fully described. It should be noted that the implementations not shown or described in the accompanying drawings are the forms known to those of ordinary skill in the art. Additionally, although examples of parameters including specific values may be provided herein, it should be understood that the parameters need not be exactly equal to the corresponding values, but may be approximated within acceptable error tolerances or design constraints. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. In addition, the terms "comprising" and "having" and any variations thereof in the description and claims of the present invention are intended to cover non-exclusive inclusion, for example, a process, method, device comprising a series of steps or units , products or devices are not necessarily limited to those steps or units expressly listed, but may include other steps or units not expressly listed or inherent to these processes, methods, products or devices.

In one embodiment of the present invention, a method for manufacturing a planar bismuth telluride-based thin-film thermoelectric module is provided, which is characterized by comprising the following steps:

S1, deposit a silicon dioxide film layer on the heat sink substrate;

S2, preparing a plurality of metal strips arranged at intervals on the silicon dioxide film layer;

S3. Alternately deposit a P-type bismuth telluride-based thin film and an N-type bismuth telluride-based thin film on the upper surface of the silicon dioxide film between different metal strips, so that P-type tellurium is deposited on one side of each metal strip A bismuthide-based film, and an N-type bismuth telluride-based film is deposited on the other side to obtain a first semi-finished product;

S4. Coat the photoresist on the upper surface of the first semi-finished product, and remove the photoresist on part of the metal strips, so that the metal strips with the photoresist removed and the metal strips without the photoresist are alternately arranged ;

S5, depositing a metal layer on the metal strip from which the photoresist is removed to obtain a second semi-finished product;

S6, coating photoresist on the upper surface of the second semi-finished product, and removing the photoresist on the metal layer deposited in step S5;

S7, depositing a thermally conductive insulating layer on the metal layer from which the photoresist was removed.

Wherein, before step S1, it also includes: performing micro-arc oxidation treatment on both the upper and lower surfaces of the heat sink substrate to obtain a ceramic oxide layer, and the thickness of the ceramic oxide layer is in the range of 5-15 μm; after performing step S7, it also includes depositing performing a removing operation on the thermally conductive insulating layer other than the metal layer, specifically removing the redundant thermally conductive insulating layer by electron beam evaporation;

Specifically, the thickness of the silicon dioxide film layer deposited in step S1 is 80-120 μm, and the amorphous silicon film with loose structure is rapidly deposited by the PECVD method and obtained by high temperature oxidation with wet oxygen, wherein the amorphous silicon film has a thickness of 80-120 μm. The density is less than 2.2 g/cm ³ ; the thickness of the metal strip prepared in the step S2 is 10-30 μm, preferably 20 μm, the length is in the range of 15-30 mm, preferably 20 mm, and the width is in the range of 0.8-1.2 μm, preferably 1 μm; the thickness range of the P-type bismuth telluride-based thin film and the N-type bismuth telluride-based thin film deposited in step S3 is both 30-80 nm, preferably 50 nm, and the length range is 0.8-1.2 μm, both are 0.8-1.2 μm. It is preferably 1 μm, and the width is in the range of 0.6-0.8 μm, preferably 0.7 μm; the photoresist coated in step S4 and the photoresist coated in step S6 are both spin-coated by a glue spinner, and their thickness ranges Both are 50-100 μm, preferably SU8 photoresist; the thickness range of the metal layer deposited in the S5 step is 50-100 μm; the thickness of the thermally conductive insulating layer in the S7 step is 50-100 μm, and the thermally conductive insulating layer is made of nitrided aluminum; in steps S3 to S7, the metal strip, P-type bismuth telluride-based thin film, N-type bismuth telluride-based thin film, and metal layer are deposited by processes such as masks, electron beam evaporation, and photolithography. Remove photoresist, thermally conductive insulating layer. It should be noted that the silicon dioxide film layer deposited on the heat sink substrate in this embodiment is mainly to facilitate the photolithography of the above-mentioned metal strips and bismuth telluride-based thin films, and has certain electrical and thermal insulation properties. , based on the function of the silicon dioxide film layer, if it is a simple replacement of the silicon dioxide film layer material, it is also within the protection scope of this embodiment. For example, the silicon dioxide film layer can be formed by doping to form a silicon oxynitride film layer, which has Similar function to silicon dioxide film, but with better electrical and thermal insulation properties.

In one embodiment of the present invention, the heat sink substrate is an aluminum substrate that has been subjected to surface micro-arc oxidation treatment. The micro-arc oxidation can be controlled by plasma electrolysis process parameters to modulate the thickness, density and thermal properties of the oxide layer. Conductivity, the aluminum substrate can also be replaced with a copper substrate for surface micro-arc oxidation treatment according to requirements. The upper and lower surfaces of the heat sink substrate are ceramic oxide layers. The thickness of the ceramic oxide layer ranges from 5 to 15 μm, preferably 10 μm. ; The material of the metal layer and the material of the corresponding deposited metal strip can be the same or different. For example, when the metal strip is preferably an aluminum strip, the deposited metal layer can be an aluminum layer, or a gold layer or a silver layer. Under the premise that the aluminum strip can be replaced by silver strip or gold strip, the present invention does not limit the three materials of aluminum, gold and silver, and the thermal conductivity is greater than or equal to 200W/(m·K) or the electrical conductivity is greater than or equal to 3E+07S The technical solution of the present invention can be realized by the metal material of /m, and the higher the thermal conductivity/electrical conductivity, the higher the thermoelectric conversion efficiency and output power density of the TE generator under the same working conditions.

In one embodiment of the present invention, a planar bismuth telluride-based thin film thermoelectric module is provided, referring to FIG. 1 and FIG. 2 , comprising a heat sink substrate 1, a silicon dioxide film layer 2, a plurality of first metal strips 3, A plurality of second metal strips 4, a bismuth telluride-based film, a photoresist 8 and a thermally conductive insulating layer 7; the heat sink substrate 1 is an aluminum substrate or a copper substrate, preferably an aluminum substrate; the silicon dioxide film layer 2 are arranged on the upper surface of the heat sink substrate 1; the first metal strips 3 and the second metal strips 4 are alternately arranged on the upper surface of the silicon dioxide film layer 2, and the first metal strips 3. The material of the second metal strip 4 is the same or different. The first metal strip 3 and the second metal strip 4 are made of aluminum, gold or silver. Both the metal strips 3 and the second metal strips 4 are preferably aluminum strips; the adjacent first metal strips 3 and the second metal strips 4 are connected and conducted through the bismuth telluride-based thin film deposited on the silicon dioxide film layer 2 . Generally, the bismuth telluride-based film includes a P-type bismuth telluride-based film 5 and an N-type bismuth telluride-based film 6, and the P-type bismuth telluride-based film 5 and the N-type bismuth telluride-based film 6 are the symbols of the Seebeck coefficient. For thermoelectric materials deposited in the opposite direction of planar heat flow, different types of bismuth telluride-based thin films are distributed on both sides of the first metal strip 3 and the second metal strip 4, and the adjacent first metal strips One or more bismuth telluride-based thin films of the same type are distributed between the belt 3 and the second metal belt 4;

The surface of the second metal strip 4 is covered by the thermally conductive insulating layer 7, preferably made of aluminum nitride, and the thermally conductive insulating layer is used as a heat source interface for heat injection, except by the The surfaces covered by the thermally conductive insulating layer 7 are all covered by the photoresist 8 , and the height of the thermally conductive insulating layer 7 is greater than the height of the photoresist 8 .

In an embodiment of the present invention, the adjacent first metal strips 3 and the second metal strips 4 are arranged at equal intervals, and the width of the first metal strips 3 is the same as the width of the second metal strips 4 The width is the same, the thickness of the second metal strip 4 is not less than the thickness of the first metal strip 3, preferably, the thickness of the second metal strip 4 is 60 μm larger than the thickness of the first metal strip 3, so The thickness of the first metal strip 3 is 10-30 μm, the lengths of the first metal strips 3 and the second metal strips 4 are both 15-30 mm, preferably 20 mm, and the widths are both 0.8-1.2 μm, preferably is 1 μm;

The P-type bismuth telluride-based thin film 5 and the N-type bismuth telluride-based thin film 6 are alternately arranged in rows on the upper surface of the silicon dioxide film layer 2, and the P-type bismuth telluride-based thin film 5 The length of the N-type bismuth telluride-based thin film 6 is equal to the distance between the adjacent first metal strips 3 and the second metal strips 4, and the adjacent first metal strips 3 and the The spacing in the longitudinal direction of the plurality of the same type of bismuth telluride-based thin films between the second metal strips 4 is equal to the width of the same type of bismuth telluride-based thin films.

In one embodiment of the present invention, the length and width of the P-type bismuth telluride-based thin film and the N-type bismuth telluride-based thin film can be reduced to less than 100 nm on a higher-resolution processing platform to obtain higher Thermoelectric material properties and energy conversion efficiency; the synergistic control between the size parameters of each film in steps S1 to S5 can modulate the heat flow transport and current transport properties to obtain the highest electrical transport performance and the lowest heat transport performance, so The above process flow is also applicable to the preparation of the gradient thermoelectric material energy conversion TE planar thin film generator. It should be noted that the manufacturing method of this embodiment is also applicable to the preparation of short planar thin film thermoelectric material TE generators with different components and no cavity structure. , the bismuth telluride-based thin film in this embodiment can be replaced with similar high-quality thermoelectric materials such as lead telluride-based and germanium-silicon-based, and these equivalently replaced materials are also within the protection scope of this embodiment.

In one embodiment of the present invention, a thermoelectric generator is provided, including the above-mentioned planar bismuth telluride-based thin film thermoelectric module.

In an embodiment of the present invention, referring to FIG. 3 , the second metal strip 4 is in direct contact with the heat source through the thermally conductive insulating layer 7 on its surface for heat transfer, thereby forming a high temperature end at its bottom, and the first metal strip 3 passes through the heat source The heat transfer forms a low temperature end at its bottom, the first metal strip 3 and the second metal strip 4 on one side are connected through a P-type bismuth telluride-based film 5, and a temperature difference occurs between the two ends of the P-type bismuth telluride-based film 5 , see Fig. 2, the bismuth telluride-based thin-film generator without a cavity structure, as shown by the thick arrows, the heat flow is perpendicular to the silicon substrate, as shown by the thin arrows, the heat flux will be steep in the bismuth-telluride-based thin film A relatively steep temperature gradient can be obtained by using a shorter bismuth telluride-based thin film generator array. Due to the Seebeck effect, the carriers on the P-type bismuth telluride-based thin film 5 move from the high temperature end to the low temperature A potential difference is formed at the ends, and the potential of the first metal strip 3 is smaller than the potential of the second metal strip 4 connected to the same P-type bismuth telluride-based thin film 5. Similarly, the first metal strip 3 is connected to the second metal strip on the other side. The belt 4 is connected through the N-type bismuth telluride-based film 6, and the two ends of the N-type bismuth telluride-based film 6 also form a potential difference, but due to the plug of the N-type bismuth telluride-based film 6 and the P-type bismuth telluride-based film 5 The Beck coefficients have opposite signs, so that the potential of the first metal strip 3 is higher than the potential of the second metal strip 4 connected to the same N-type bismuth telluride-based thin film 6, and the currents formed by the above two potential differences are in the same direction, so that the first There is a larger potential difference between the second metal strips 4 at both ends of the metal strip 3, and there are multiple bismuth telluride-based thin films between the adjacent first metal strips 3 and the second metal strips 4, and there are multiple groups of the above The first metal strip 3 and the second metal strip 4 finally obtain a further enlarged potential difference, so as to improve the power generation of higher power. It should be noted that the Seebeck effect belongs to the prior art, and the cause of the Seebeck effect can be simply explained that the carriers in the conductor move from the hot end to the cold end under the temperature gradient, and accumulate at the cold end, so as to A potential difference is formed inside the material, and a reverse charge flow is generated under the action of the potential difference. When the charge flow of thermal motion and the internal electric field reach a dynamic balance, a stable thermoelectric potential is formed at both ends of the semiconductor. There are two types of carriers in the semiconductor, namely electrons and holes.

The invention relates to a design method of a semiconductor device, in particular to a design method of a semiconductor thermoelectric generator, to be precise, a planar bismuth telluride-based thin film thermoelectric device designed and prepared by combining MEMS micromachining technology and thin film deposition technology (TE) Generator design and fabrication method. In order to solve the problems of low efficiency, large temperature difference, and difficult realization of high energy density heat sources of existing semiconductor thermoelectric devices, the present invention provides a preparation method of a planar bismuth telluride-based thin film thermoelectric (TE) generator to overcome the problems of the prior art. Insufficiency; the present invention obtains an effective temperature gradient maintaining structure through novel heat source and heat sink material selection and structural design, and then utilizes the properties of the opposite signs of Seebeck coefficients of P-type/N-type thermoelectric materials to deposit P-type/N-type thermoelectric materials in the direction of planar heat flow transfer. N-type thermoelectric material, a thermoelectric (TE) generator with a power density of 20 mW/cm ² under a temperature difference of 5 °C was obtained.

The method for manufacturing the planar bismuth telluride-based thin film thermoelectric module, the thermoelectric module and the thermoelectric generator proposed by the invention utilizes MEMS micromachining technology and thin film deposition technology to design and prepare a short-plane thin-film bismuth telluride-based thermoelectric generator without cavity structure. This novel design concept takes advantage of the steep temperature gradient formed near the main heat flow, by shortening the bismuth telluride-based-NWs to submicron lengths, compared with conventional planar bismuth telluride-based thermoelectric generators, the power generation of the present invention The power density of the machine is more scalable. The heat flow and current transmission thermoelectric device designed by the invention can greatly promote the performance of semiconductor thermoelectric device, and can be widely used in portable, wearable and distributed sensor network systems and other fields.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (10)

1. A manufacturing method of a planar bismuth telluride-based thin film thermoelectric module is characterized by comprising the following steps:

s1, depositing a silicon dioxide film layer on the heat sink substrate;

s2, preparing a plurality of metal strips arranged at intervals on the silicon dioxide film layer;

s3, alternately depositing a P-type bismuth telluride-based film and an N-type bismuth telluride-based film on the upper surface of the silicon dioxide film layer between different metal strips, so that the P-type bismuth telluride-based film is deposited on one side of each metal strip, and the N-type bismuth telluride-based film is deposited on the other side of each metal strip, and obtaining a first semi-finished product;

s4, coating photoresist on the upper surface of the first semi-finished product, removing the photoresist on part of the metal strips, and enabling the metal strips with the photoresist removed and the metal strips without the photoresist removed to be alternately arranged;

s5, depositing a metal layer on the metal strip with the photoresist removed to obtain a second semi-finished product;

s6, coating photoresist on the upper surface of the second semi-finished product, and removing the photoresist on the metal layer deposited in the step S5;

and S7, depositing a heat conduction insulating layer on the metal layer with the photoresist removed.

2. The method of claim 1, wherein after step S7, the method further comprises removing the thermally conductive and insulating layer deposited on the metal layer.

3. The method of manufacturing a planar bismuth telluride-based thin film thermoelectric module as claimed in claim 1, wherein step S1 is preceded by the steps of: and (3) carrying out micro-arc oxidation treatment on the upper surface and the lower surface of the heat sink substrate to obtain a ceramic oxide layer, wherein the thickness range of the ceramic oxide layer is 5-15 mu m.

4. The method of manufacturing a planar bismuth telluride-based thin film thermoelectric module as claimed in claim 1, wherein the metal tape has a thickness in the range of 10 to 30 μm, a length in the range of 15 to 30mm, and a width in the range of 0.8 to 1.2 μm; the thickness ranges of the P-type bismuth telluride-based thin film and the N-type bismuth telluride-based thin film are both 30-80nm, the length ranges are both 0.8-1.2 mu m, and the width ranges are both 0.6-0.8 mu m.

5. The method for manufacturing a planar bismuth telluride-based thin film thermoelectric module as claimed in claim 1, wherein the thickness of the silicon dioxide film layer deposited in the step S1 is 80-120 μm, and the amorphous silicon film is rapidly deposited by a PECVD method and then oxidized at high temperature by wet oxygen to obtain the planar bismuth telluride-based thin film thermoelectric module; the thickness of the photoresist coated in the step S4 and the thickness of the photoresist coated in the step S6 are both 50-100 μm; the thickness of the metal layer deposited in the step S5 is in the range of 50-100 mu m; the thickness of the heat conductive insulating layer in the step S7 is in the range of 50 to 100 μm, and the heat conductive insulating layer is made of aluminum nitride.

6. The planar bismuth telluride-based thin film thermoelectric module is characterized by comprising a heat sink substrate (1), a silicon dioxide film layer (2), a plurality of first metal strips (3), a plurality of second metal strips (4), a bismuth telluride-based thin film, a photoresist (8) and a heat conduction insulating layer (7), wherein the silicon dioxide film layer (2) is arranged on the upper surface of the heat sink substrate (1), and the first metal strips (3) and the second metal strips (4) are alternately arranged on the upper surface of the silicon dioxide film layer (2) at intervals; the first metal belt (3) and the second metal belt (4) which are adjacent are connected and conducted through a bismuth telluride-based film deposited on the silicon dioxide film layer (2), the bismuth telluride-based film comprises a P-type bismuth telluride-based film (5) and an N-type bismuth telluride-based film (6), different types of bismuth telluride-based films are distributed on two sides of the first metal belt (3) and two sides of the second metal belt (4), and one or more same types of bismuth telluride-based films are distributed between the first metal belt (3) and the second metal belt (4) which are adjacent;

the surface of the second metal strap (4) is covered by the heat conduction insulating layer (7), the surface covered by the heat conduction insulating layer (7) is covered by the photoresist (8), and the height of the heat conduction insulating layer (7) is larger than that of the photoresist (8).

7. The planar bismuth telluride-based thin film thermoelectric module according to claim 6, wherein the first metal strip (3) and the second metal strip (4) are arranged at equal intervals, the width of the first metal strip (3) is the same as that of the second metal strip (4), and the length of the P-type bismuth telluride-based thin film (5) and the length of the N-type bismuth telluride-based thin film (6) are both equal to the distance between the first metal strip (3) and the second metal strip (4).

8. The planar bismuth telluride-based thin film thermoelectric module according to claim 7, wherein the thickness of the second metal strip (4) is not less than the thickness of the first metal strip (3), the thickness of the first metal strip (3) is in the range of 10 to 30 μm, the length of each of the first metal strip (3) and the second metal strip (4) is in the range of 15 to 30mm, the width of each of the first metal strip and the second metal strip is in the range of 0.8 to 1.2 μm, the first metal strip (3) and the second metal strip (4) are made of the same or different material, and the first metal strip (3) and the second metal strip (4) are made of aluminum, gold, or silver.

9. The planar bismuth telluride-based thin film thermoelectric module as claimed in claim 8, wherein the P-type bismuth telluride-based thin films (5) and the N-type bismuth telluride-based thin films (6) are alternately arranged in a row on the upper surface of the silicon dioxide film layer (2);

the distance between the first metal belt (3) and the second metal belt (4) which are adjacent to each other in the longitudinal direction of the plurality of bismuth telluride-based films of the same type is equal to the width of the bismuth telluride-based films of the same type.

10. A thermoelectric generator comprising a planar bismuth telluride-based thin film thermoelectric module as claimed in claims 6 to 9.

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