CN113176293A - Structure and method for measuring heterojunction interface thermal conductivity by adopting lattice contact mode - Google Patents
Structure and method for measuring heterojunction interface thermal conductivity by adopting lattice contact mode Download PDFInfo
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Abstract
本发明公开了一种采用点阵接触方式测量异质结界面热导率的结构及方法，属于半导体材料及器件的电学和热学测试技术领域。所处测量结构包括：测温芯片和被测样品，其中测温芯片包括由多个二极管或肖特基结串联形成的测温端，以及由多晶硅图形的微加热器结构；被测样品由两种半导体材料及其异质结构界面组成，表面经过光刻等工艺处理，形成均匀分布的矩形矩阵。本发明通过设计一种测温芯片，将测温芯片与被测材料通过点阵矩阵的接触方式，通过测温芯片采集温度响应曲线，对被测材料建立热仿真模型并迭代异质结界面热导率进行求解，直至模型解与实际采集的温度响应曲线一致，即可提取出被测材料异质结界面的热导率。
The invention discloses a structure and a method for measuring the thermal conductivity of a heterojunction interface by using a lattice contact method, and belongs to the technical field of electrical and thermal testing of semiconductor materials and devices. The measurement structure includes: a temperature measurement chip and a sample to be measured, wherein the temperature measurement chip includes a temperature measurement terminal formed by a plurality of diodes or Schottky junctions in series, and a micro-heater structure formed of polysilicon patterns; the sample to be measured consists of two It is composed of a semiconductor material and its heterostructure interface, and the surface is processed by photolithography and other processes to form a uniformly distributed rectangular matrix. The invention designs a temperature measuring chip, connects the temperature measuring chip and the measured material through the contact mode of the lattice matrix, collects the temperature response curve through the temperature measuring chip, establishes a thermal simulation model for the measured material, and iterates the heat of the heterojunction interface. The thermal conductivity of the measured material heterojunction interface can be extracted until the model solution is consistent with the actual temperature response curve.
Description
The technical field is as follows:
the invention discloses a structure and a method for measuring the thermal conductivity of a heterojunction interface by adopting a lattice contact mode, belonging to the technical field of electrical and thermal measurement of semiconductor materials and devices.
Background art:
in order to meet the increasing high-performance requirements, heterostructure materials are important choices of novel semiconductor chips in the future, so that the advantages of different materials in electricity, optics, thermal engineering and the like are fully exerted. Besides basic material properties such as morphology and components, the temperature rise and thermal resistance of the heterostructure interface are one of the most interesting characteristics in material research and device preparation. The method not only influences the microscopic electron transport and performance of the device, but also influences the reliability of a macroscopic system, and the accumulation of any thermal resistance of a thin-layer structure finally increases the temperature of a system core area. Compared with the good compactness and integrity of a bulk material, the heterogeneous material interface is often subjected to the phenomena of material defect increase, phonon mismatch and the like caused by lattice mismatch and growth process limitation, so that the total thermal resistance of the material interface is far higher than an expected value, the overall heat dissipation performance of the device is influenced, and the heterogeneous material interface becomes a key factor for restricting the development of the heterogeneous material device. The conventional method mainly uses an optical method of a Time-Domain thermal reflection spectrum (TDTR) and a Transient thermal emission spectrum (TTM) of "pump-probe", and the conventional method usually requires a large and expensive optical device for measurement, and is not suitable for large-scale measurement due to complex measurement operation.
The invention content is as follows:
the invention aims to solve the problems, a lattice array form is etched on the surface of a material to be measured, a thermal contact mode is adopted to collect a temperature response curve of the material to be measured, and finally the thermal conductivity of a heterojunction interface in the material to be measured is extracted in a numerical simulation mode.
In order to achieve the purpose, the invention adopts the following technical scheme:
a temperature measuring chip with a heat source is tightly attached to the surface of a measured material, has independent heat source and temperature measuring functions, and can respectively realize independent control of heat source heating and temperature response acquisition. And etching the surface of the material to be detected to form a dot matrix rectangular matrix with the same depth, the same size and uniform distribution by a photoetching process. During measurement, a heating or cooling response curve of a measured sample is collected under the control of a computer, and the thermal conductivity of a heterojunction interface in a measured material is finally extracted through numerical simulation.
The advantage of using lattice contact mode to measure the heterojunction interface thermal conductivity is that: 1. the heating structure and the temperature measuring structure of the temperature measuring chip are completely independent and can be independently controlled by a computer, so that the collection of a heating response curve, a cooling response curve and an unsteady response curve (pulse and sine) is realized; 2. after the dot-shaped rectangular array is etched on the surface of the material to be detected, the proportion of the temperature rise of the heterojunction interface layer in the total temperature response curve can be effectively improved, and the sensitivity and the accuracy of thermal conductivity extraction are improved; 3. compared with an optical measurement method, the lattice contact measurement method is simple and convenient to operate, and can realize rapid measurement of thermal conductivity.
The utility model provides an adopt lattice contact mode to measure heterojunction interface thermal conductivity's structural design which characterized in that:
the structure main body for measuring the heterojunction interface thermal conductivity by the lattice contact mode comprises: 100: temperature measurement chip, 110: measured material, 121: a constant temperature platform;
the temperature measurement chip structure 100 includes: 101: a heating source; 102: a temperature measuring end;
the material structure under test 110 includes: 111: a heterojunction material 1; 112: a heterojunction interface; 113: a heterojunction material 2;
the structure for measuring the heterojunction interface thermal conductivity by applying the lattice contact mode consisting of the structures is characterized in that:
the structure for measuring the heterojunction interface thermal conductivity in a lattice contact mode consists of a temperature measuring chip 100, a material to be measured 110 and a constant temperature platform 121; the temperature measurement chip 100 comprises a heating source 101 and a temperature measurement end 102; the heating source 101 is a micro-heater composed of polysilicon, metal wire or doped Si, and constant electric power is applied to both ends of the micro-heater, so that stable thermal power can be generated due to joule effect; the temperature measuring end 102 is a temperature probe composed of a PN junction or a Schottky junction; the tested material 110 comprises 111 heterojunction material 1, 112 heterojunction interface and 113 heterojunction material 2; the tested material 110 is etched to form dot-shaped rectangular matrixes with the same depth, the same size and uniform distribution on the surface through single or multiple photoetching, the area, the number and the spacing distance of the dot-shaped matrixes can be defined through different photoetching plates, and the etching depth needs to exceed the depth of a heterojunction interface by 1-10 mu m; the constant temperature stage 121 provides a fixed ambient temperature for the measurement and provides a good heat dissipation path for the entire measurement system.
The method for measuring the heterojunction interface thermal conductivity in the lattice contact mode comprises the following steps: 100: temperature measurement chip, 110: measured material, 121: a constant temperature platform; 200: a measurement system; 300: controlling an industrial personal computer;
the measurement circuit includes: 201: a power supply; 202: a constant current source circuit and an acquisition circuit; 203: a pressure control device;
the method for measuring the heterojunction interface thermal conductivity by using the point contact mode is characterized by comprising the following steps:
when the measurement is started, the material to be measured is placed on the constant temperature platform, and the temperature of the constant temperature platform is set to be T1. The temperature measuring chip 100 is tightly attached to the surface of the material 110 to be measured, and the pressure control module 203 in the measuring system 200 sets the applied pressure N1The heating source 101 and the temperature measuring end 102 in the temperature measuring chip 100 are respectively connected with the power supply 201 and the constant current source circuit and the acquisition circuit 202 in the measuring system; the heating power W is respectively set by the industrial control computer 3001Heating time t1Cooling time t2Constant current source current I1(ii) a While applying heating power W1At the later initial moment, the industrial control computer 300 controls the constant current source circuit and the acquisition circuit 202 to start acquiring the voltage at the two ends of the temperature measurement chip 102 at the constant current source current I1Under the action of voltage change along with temperature, the temperature rise response curve of the material to be detected can be obtained through the relation between the voltage and the temperature; time lapse t1Then, the industrial control computer 300 cuts off the heating power and continues to collect the voltage at the two ends of the temperature measurement chip at the constant current source current I1The temperature drop response curve of the material to be detected can be obtained along with the change of the temperature under the action; inputting the thickness d, specific heat capacity c, density rho, thermal conductivity k and the like of the known material information of the material to be measured into an industrial control computer, solving and calculating a heat conduction equation in a numerical simulation mode, and calculating unknown quantity (heterojunction interface thermal conductivity)Continuously performing iterative computation to enable the temperature response curve obtained by solving to be consistent with the temperature response curve obtained by the temperature measurement chip 100, and indicating that the heterojunction interface thermal conductivity obtained by iterative computation at the moment is the actual thermal conductivity of the heterojunction interface of the material to be measured;
description of the drawings:
FIG. 1 is a schematic structural diagram of a lattice contact method for measuring the thermal conductivity of a heterojunction interface;
wherein, 100: a temperature measuring chip; 101: a heating source; 102: a temperature measuring end; 110: a material to be tested; 111: a heterojunction material 1; 112: a heterojunction interface; 113: a heterojunction material 2; 121: a constant temperature platform;
FIG. 2 is a schematic diagram of a lattice contact method for measuring the thermal conductivity of a heterojunction interface;
wherein, 100: a temperature measuring chip; 101: a heating source; 102: a temperature measuring end; 110: a material to be tested; 111: a heterojunction material 1; 112: a heterojunction interface; 113: a heterojunction material 2; 121: a constant temperature platform; 200: a measurement system; 201: a power supply; 202: a constant current source circuit and an acquisition circuit; 203: a pressure control device; 300: industrial control computer
The specific implementation mode is as follows:
the invention is further described with reference to the following figures and detailed description:
fig. 2 is a schematic diagram of measuring the thermal conductivity of the heterojunction interface in a lattice contact manner, which includes, 100: a temperature measuring chip; 101: a heating source; 102: a temperature measuring end; 110: a material to be tested; 111: a heterojunction material 1; 112: a heterojunction interface; 113: a heterojunction material 2; 121: a constant temperature platform; 200: a measurement system; 201: a power supply; 202: a constant current source circuit and an acquisition circuit; 203: a pressure control device;
the temperature measuring chip 100 is manufactured by a heating source 101 and a temperature measuring end 102 on a semiconductor substrate material through semiconductor processes such as photoetching, etching and the like;
the total chip area of the temperature measuring chip 100 is about 1mm multiplied by 1mm, wherein the heating source 101 is made by depositing and etching polycrystalline silicon, and the generated heat flow can form uniform temperature distribution on one side of the measuring source through corresponding graphic design; the temperature measuring end 102 is formed by connecting 9 diodes in series and manufacturing the diodes through semiconductor processes such as photoetching, etching and the like, the forward junction voltage drop of the temperature measuring end is about-18 mV/DEG C along with the change of the temperature, and the change amplitude of the temperature probe along with the temperature is greatly improved, so that tiny temperature change information is captured, and the signal-to-noise ratio of the temperature probe is improved.
The tested material 110 is made of a heterojunction material 1111 and a heterojunction interface 112 on a heterojunction material 2113 through a standard epitaxial growth process; the thicknesses of the heterojunction material 1111, the heterojunction interface 112 and the heterojunction material 2113 are about 2 μm, 100nm and 300 μm, respectively; through a single photoetching process, 10 multiplied by 10 evenly distributed rectangular matrixes are etched at the center of the surface of the heterojunction material 1111, the total area of the matrixes is about 100 microns multiplied by 100 microns, the area of each single matrix is about 10 microns multiplied by 10 microns, and the etching depth is about 5-10 microns;
before the measured material is measured, the same rectangular matrix is etched on the surface of the standard Si sample through the same etching process. A standard Si sample is placed on the thermostatic stage 121, and the thermostatic stage 121 temperature is set to T. And (3) tightly attaching the temperature measuring chip 100 to the surface of the etched standard Si sample. The industrial control computer 300 controls the measurement system 200 to apply heating power W, constant current source I, pressure N and heating time t to the temperature measurement chip 1001Cooling time t2. The temperature measuring chip 100 collects the temperature at the heating time t1And cooling time t2Temperature response curve in process. Various parameters of the temperature measuring chip 100 and the standard Si sample are input into the industrial control computer 300, the thermal contact resistance of the temperature measuring chip 100 and the standard Si sample is determined through numerical calculation, and other measurement parameters are calibrated until the temperature response curve calculated in the model is consistent with the actually acquired temperature response curve.
The standard Si sample is replaced with the measured sample 110, and since the contact resistance at this time is only related to the pressure N, the contact resistance can be considered to be the same at the same pressure. Other parameters can be adjusted in response to different samples to be tested and test conditions. For ease of discussion, the same measurement conditions as for the standard Si sample were used in this example. The industrial control computer 300 controls the measuring system 200 to apply the same addition to the temperature measuring chip 100Heating power W, constant current source I, pressure N and heating time t1Cooling time t2. The temperature measuring chip 100 collects the temperature at the heating time t1And cooling time t2Temperature response curve in process. Inputting the material parameters of the temperature measuring chip 100, the thermal contact resistance between the measured sample 110 and the temperature measuring chip 100 and other known parameters except the heterojunction interface thermal conductivity in the measured sample into the industrial control computer 300, and continuously iterating the parameters of the heterojunction interface thermal conductivity in the model through numerical calculation until the temperature response curve calculated in the model is consistent with the actually acquired temperature response curve. The heterojunction interface thermal conductivity in the model at this time can be considered as an actual value of the heterojunction interface thermal conductivity in the measured material.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117929465A (en) * | 2024-01-29 | 2024-04-26 | 纳宇半导体材料(深圳)有限责任公司 | Thermal conductivity testing method and system of thermal interface materials based on thermal testing chip |
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| US20090084959A1 (en) * | 2005-03-15 | 2009-04-02 | Hudgings Janice A | Methods of Thermoreflectance Thermography |
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