CN111060555A - Method and device for measuring thermal conductivity and thermal diffusivity of thin film material under strain - Google Patents

Abstract

The invention discloses a method and a device for measuring the thermal conductivity and thermal diffusivity of a thin film material under strain, wherein a sample is tensioned by a tensioning mechanism, the sample, the tensioning mechanism and a driving mechanism are placed in a vacuum chamber, the sample is heated by laser, a temperature distribution diagram of the sample in the whole process from the beginning to the steady state under fixed strain is obtained by an infrared camera, the thin film is treated as two-dimensional heat transfer, an experimental picture is processed to obtain the temperature of each pixel point on the surface of the thin film, the thin film is divided into a plurality of infinitesimals according to the size of the pixel point, a steady state thermal equilibrium equation and a transient thermal equilibrium equation are established, the thermal conductivity and the thermal diffusivity of the thin film under different temperatures are solved, the driving mechanism drives the sample to generate different strains, and the condition that the thermal conductivity and the thermal diffusivity of the sample under different. The method is convenient to operate, has high measurement accuracy, and can obtain the condition that the thermal conductivity and the thermal diffusivity of the sample change along with the temperature under different strains.

Description

Method and apparatus for measuring thermal conductivity and thermal diffusivity of thin film materials under strain

technical field

The invention belongs to the technical field of heat transfer, and in particular relates to a method and a device for measuring the thermal conductivity and thermal diffusivity of thin film materials under strain.

Background technique

Thin films are not only the most effective materials for miniaturizing devices and systems, but in the field of sensors, thin films are also used as one of the components to measure different physical quantities. The working temperature of the film is generally changed, and in the process of use, due to the transfer, vibration and heat generation, it will also be subjected to different degrees of stress to produce small strains. The reliability of the device or system needs to be verified after the thermal properties of the film are changed. Therefore, it is important to correctly determine the relationship between the thermal conductivity and thermal diffusivity of the film under strain and temperature to determine the reliability of the system to improve the design of electronic devices. significance.

However, the current technical solutions for measuring the thermal conductivity and thermal diffusivity of thin-film materials have some defects:

Infrared imaging technology is a method to obtain the temperature of the object by receiving the radiant energy of the surface of the object. By calibrating the emissivity of the object surface, the temperature of each pixel can be accurately obtained, and the temperature resolution is high; in the patent (authorized announcement number CN 109001250 A) In "Analysis Method of Thermal Conductivity of Thin Films Based on Infrared Imaging", after obtaining the temperature distribution based on infrared thermal imaging technology, input the boundary conditions of the model, and set the thermal conductivity of thin films as 70% to 100% of the theoretical value for simulation, When the simulated temperature distribution curve is consistent with the test results, the value of the thermal conductivity of the film is obtained. The existing problems are that the theoretical value of thermal conductivity of the material needs to be known in advance, which has limitations; the second is that the value of thermal conductivity needs to be modified many times on this basis to match the test temperature distribution diagram, which requires a lot of work and errors. very large.

In the patent (authorized bulletin number CN 106813718 A) "a device and method for measuring the strain and thermal conductivity of thin films", although the thermal conductivity of the conductive thin film material under different strains can be measured, the preprocessing steps for the material are cumbersome, It is necessary to coat the film on the substrate, and then sputter four pads according to the 3ω method. At the same time, a micron-scale metal strip is made on the surface of the film, and the four pads are connected to the metal strip. In addition, this method also requires the electrical conductivity of the thin film material, and the Young's modulus can only be calculated to calculate the strain, which has many limitations.

In the patent (authorized announcement number CN 110487842 A) "device and method for simultaneously measuring in-plane thermal conductivity and infrared emissivity of thin films", the temperature distribution is formed on the surface of the thin film by light heating, and the spatial distribution of infrared radiation radiation is tested and fitted The curve gives the thermal conductivity. However, the heat equation established in this method is one-dimensional heat transfer. In fact, as a common two-dimensional material, the film cannot be ignored even if the heating light field has an aspect ratio greater than 2. The heat transfer in the width direction, so the thermal conductivity obtained by this method through the one-dimensional thermal conductivity equation has a large error.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method and device for measuring the thermal conductivity and thermal diffusivity of thin-film materials under strain. The present invention is easy to operate, has high measurement accuracy, and can obtain the variation of thermal conductivity and thermal diffusivity of samples with different strains with temperature. Case.

The technical scheme adopted in the present invention is:

A method for measuring thermal conductivity and thermal diffusivity of thin film materials under strain, comprising the steps of:

S1. Spread the sample and tension it through the tensioning mechanisms at both ends, put the sample, the tensioning mechanism and the driving mechanism into the vacuum chamber and seal and vacuumize it, so that only heat conduction and heat radiation are considered;

S2. Use a continuous laser to heat the sample in the vacuum chamber, and obtain the temperature distribution diagram of the whole process of the sample from heating to a steady state under a fixed strain through an infrared camera;

S3. Since the thickness of the film is much smaller than the side length, the film is regarded as two-dimensional heat transfer, and the experimental picture is processed to obtain the temperature of each pixel on the surface of the film, and the film is divided into several micro-elements according to the size of the pixel, thus obtaining Temperature values of different microelements under fixed strain;

S4. Establish steady-state and transient heat balance equations, and solve the thermal conductivity and thermal diffusivity of the film at different temperatures;

S5. The driving mechanism drives the tensioning mechanism to control the sample to generate a small displacement Δx, and the sample generates different strains. According to steps S2 to S4, the thermal conductivity and thermal diffusivity of the sample change with temperature under different strains.

Further, in step S4, the established steady state process

established transient process

in,

代表微元在x的负方向由于热传导流入的热量；

Represents the heat flowing into the micro-element in the negative direction of x due to thermal conduction;

代表微元在x的正方向由于热传导流入的热量；

Represents the heat flowing into the micro-element in the positive direction of x due to heat conduction;

代表微元在y的负方向由于热传导流入的热量；

Represents the heat flowing into the micro-element in the negative direction of y due to heat conduction;

代表微元在y的正方向由于热传导流入的热量；

Represents the heat flowing into the micro-element in the positive direction of y due to heat conduction;

where Δx and Δy represent the lengths of the micro-element in the x and y directions, respectively, λ _{(m, n)} represents the thermal conductivity of the micro-element, d represents the thickness of the sample, T _{(m-1, n)} and T _{(m+1 , n)} respectively represent the temperature of the two units before and after the micro-element in the x direction, T _{(m, n-1)} and T _{(m, n+1)} respectively represent the temperature of the two units before and after the micro-element in the y direction;

PΔxΔy represents the heat of laser heating flowing into the micro-element, where P is the laser incident intensity;

代表微元上下与周围环境的辐射换热，其中ε是样品的发射率，σ是玻尔兹曼常数，T_(m，n)代表微元的温度，T₀代表环境温度，考虑到样品的上下表面与周围环境都有辐射换热，因此乘2；

Represents the radiative heat exchange between the upper and lower micro-elements and the surrounding environment, where ε is the emissivity of the sample, σ is the Boltzmann constant, T _{(m, n)} represents the temperature of the micro-element, T ₀ represents the ambient temperature, considering the sample's emissivity There is radiation heat exchange between the upper and lower surfaces and the surrounding environment, so multiply by 2;

代表在时间Δτ内微元由于温度上升引发的内能变化，其中

和

分别代表微元在该时刻和后一时刻的温度，a代表薄膜材料的热扩散系数。

Represents the change in internal energy of the element due to temperature rise during time Δτ, where

and

respectively represent the temperature of the micro-element at this moment and the next moment, and a represents the thermal diffusivity of the film material.

Further, before the measurement, first determine the emissivity of the sample, measure the temperature of the sample surface with a thermocouple and adjust the emissivity of the infrared camera until the surface temperature measured by the infrared camera is the same as the temperature measured by the thermocouple. The emissivity at is the true emissivity of the sample.

A device for measuring thermal conductivity and thermal diffusivity of thin-film materials under strain, comprising a vacuum cavity with a light-transmitting window, a laser probe sealed and extended into the vacuum cavity, a laser connected to the laser probe, and a vacuum chamber for evacuating the vacuum cavity. An air pump, an infrared camera facing the light-transmitting window to photograph the sample in the vacuum chamber, a data processing module connected to the infrared camera, and a tensioning mechanism and a driving mechanism located in the vacuum chamber, the tensioning mechanism is used to tension both ends of the sample and drive The mechanism is used to drive the tensioning mechanism to control the tiny displacement of the sample.

Further, the light-transmitting window adopts germanium window.

Further, the tensioning mechanism includes two parallel heat sinks located at both ends of the sample, each pair of heat sinks clamps the ends of the sample from the upper and lower sides and fastens them with bolts.

Further, the driving mechanism includes a guide rail, a rack, a motor and a gear drive train, a pair of heat sinks are fixed in position, the lower heat sink of the other pair of heat sinks is slidably fitted on the guide rail, the upper heat sink is fixed to the gear rack, and the motor The gear train is meshed with the rack, and the power cord of the motor is sealed out of the vacuum chamber and connected to the power supply.

Further, the gear train includes a motor output shaft, a pinion A on the motor output shaft, a fixed shaft, and a large gear B and a small gear C set on the fixed shaft. The pinion A meshes with the large gear B, and the pinion C engages with the rack.

其中r_A、r_B和r_C分别代表齿轮A、齿轮B和齿轮C的半径，θ₀代表电机的步距角。Further, when the motor is a stepper motor, the amount of sample stretching generated by a single pulse

where r _A , r _B and r _C represent the radii of gear A, gear B and gear C, respectively, and θ ₀ represents the step angle of the motor.

Further, the laser probe is incident on the sample obliquely.

The beneficial effects of the present invention are:

The present invention has no requirement for electrical conductivity of the film material, and does not require a pretreatment process. It is only necessary to fix both ends of the sample to be tested for measurement, and the operation is convenient; the heating method of the present invention is non-contact, which reduces the contact thermal resistance. In addition, the vacuum environment is introduced to avoid the influence of convective heat transfer, and the accuracy and convenience of calculation are improved. the thermal conductivity and thermal diffusivity under different strains; the present invention generates different strains of the sample through the driving mechanism, and can measure the thermal physical parameters under different strains; the present invention uses laser heating, the output power of the laser is adjustable, and different thermal conductivity can be studied. Capability and thermal conductivity and thermal diffusivity of materials of different sizes at different temperature levels.

Description of drawings

FIG. 1 is a schematic structural diagram of an apparatus according to an embodiment of the present invention.

FIG. 2 is a working schematic diagram of the tensioning mechanism and the driving mechanism in the embodiment of the present invention (the guide rails are omitted).

FIG. 3 is a thermal balance analysis diagram of steady-state heat transfer in a laser spot in an embodiment of the present invention.

FIG. 4 is a graph showing the relationship between the thermal conductivity of the center of the light spot and the relative position in the embodiment of the present invention.

FIG. 5 is a diagram showing the relationship between the thermal diffusivity and the relative position of the center of the light spot in the embodiment of the present invention.

FIG. 6 is a graph showing the sensitivity of temperature to thermal conductivity in an embodiment of the present invention.

FIG. 7 is a comparison diagram of inversion results of thermal conductivity at different temperatures and initial values in an embodiment of the present invention.

In the figure: 1-vacuum chamber; 2-heat sink; 3-guide rail; 4-sample; 5-gear transmission; 6-motor; 7-power supply; 8-air pump; 9-germanium window; 10-computer; 11 - Infrared camera; 12 - laser probe; 13 - laser.

Detailed ways

The invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

As shown in FIG. 1 , a device for measuring the thermal conductivity and thermal diffusivity of thin film materials under strain includes a vacuum chamber 1 with a light-transmitting window, a laser probe 12 sealed into the vacuum chamber 1, and a laser probe 12 connected to the The laser 13, the air pump 8 for evacuating the vacuum chamber 1, the infrared camera 11 facing the light-transmitting window to photograph the sample in the vacuum chamber 1 (the infrared camera 11 is installed and fixed by the support frame), and the data processing module connected with the infrared camera 11 (computer 10) and a tensioning mechanism and a driving mechanism located in the vacuum chamber 1, the tensioning mechanism is used to tension both ends of the sample 4, and the driving mechanism is used to drive the tensioning mechanism to control the sample 4 to produce tiny displacements.

Preferably, the light transmission window adopts germanium window 9 .

As shown in FIG. 1 , preferably, the laser probe 12 is incident on the sample 4 obliquely to prevent interference with the imaging of the infrared camera 11 . For samples of different sizes, the incident power and incident angle of the laser can be changed, so that the sample 4 can reach the required temperature rise.

As shown in Figures 1 and 2, preferably, the tensioning mechanism includes two heat sinks 2 that are aligned and located at both ends of the sample (the heat sink 2 can be made of tungsten copper alloy). 4 The ends are clamped and fastened with bolts.

As shown in FIGS. 1 and 2 , preferably, the driving mechanism includes a guide rail 3 , a rack D, a motor 6 and a gear train 5 , a pair of heat sinks 2 are fixed in position, and the lower side heat sink 2 of the other pair of heat sinks 2 The upper heat sink 2 is fixed to the rack D. The motor 6 is meshed with the rack D through the gear train 5. The power cord of the motor 6 is sealed out of the vacuum chamber 1 and connected to the power supply 7.

As shown in FIG. 2 , preferably, the gear train 5 includes a motor output shaft, a pinion A set on the motor output shaft, a fixed shaft, and a large gear B and a pinion C set on the fixed shaft. The pinion A and The large gear B meshes, and the pinion C meshes with the rack D.

Before measurement, first determine the emissivity of sample 4, use the thermocouple to measure the temperature of the sample surface and adjust the emissivity of the infrared camera until the surface temperature measured by the infrared camera is the same as the temperature measured by the thermocouple. The emissivity is the true emissivity of sample 4.

When measuring the thermal conductivity and thermal diffusivity of thin film materials under strain, the steps include:

S1. Put the sample 4, the tensioning mechanism and the driving mechanism into the vacuum chamber 1, a pair of heat sinks 2 are fixed on the guide rail 3, the other pair of heat sinks 2 are matched with the guide rail 3, and the two pairs of heat sinks 2 are at the same height, The sample 4 is spread out, and two pairs of heat sinks 2 are respectively clamped at both ends of the sample 4 to keep the sample 4 horizontal, and then fastened with bolts to prevent relative displacement with the heat sink 2 during the stretching process.

其中r_A、r_B和r_C分别代表齿轮A、齿轮B和齿轮C的半径，θ₀代表电机6的步距角。S2. Install the gear train 5, so that the motor 6 meshes with the rack D through the gear train 5. When the motor is a stepping motor, the amount of sample stretching generated by a single pulse

where r _A , r _B and r _C represent the radii of gear A, gear B and gear C, respectively, and θ ₀ represents the step angle of the motor 6 .

通过调整齿轮半径，该应变值还可以更小，可以随薄膜尺寸做相应调整。The total stretching amount is equal to the number of pulses multiplied by the stretching amount generated by a single pulse. For example, a two-phase stepping motor 6 is selected, the side length of the film is L _x =80mm, the step angle θ ₀ =1.8°, and the gear When the radii are r _A = r _C = 5mm and r _B = 50mm, the corresponding film stretch Δx = 15.7um generated by a single pulse, the strain

By adjusting the gear radius, the strain value can also be smaller, and can be adjusted accordingly with the film size.

S3 , cover the top cover with the germanium window 9 , and extend the laser probe 12 into the vacuum chamber 1 obliquely.

S4. After adjusting the infrared camera 11 up and down to complete the focus, fix it and maintain a stable data connection with the data processing module (computer 10).

S5. Detect the interface of the vacuum chamber 1 to ensure that the interface is sealed and air-tight, and start the air pump 8 to keep the air pressure in the vacuum chamber 1 at 1×10 ^-4 Pa.

S6. Turn on the laser, and the power and incident angle of the laser can be adjusted to provide a stable and uniform heat source for the sample 4.

At the same time, the temperature inside the vacuum chamber 1 is photographed in real time by the infrared camera 11 , and the temperature distribution map of the whole process from the start of heating to the temperature distribution reaching the temperature is obtained.

S7. Since the thickness of the film is much smaller than the side length, the sample 4 is regarded as a two-dimensional heat transfer, and the experimental picture is processed (using data processing software, such as MATLAB) to obtain the temperature of each pixel point on the surface of the sample 4. The size of the point is divided into several micro-elements, so as to obtain the temperature values of different micro-elements under a fixed strain.

S8. Establish steady-state and transient heat balance equations, and solve the thermal conductivity and thermal diffusivity of sample 4 at different temperatures.

For the steady-state two-dimensional heat transfer process, the micro-element heat balance analysis in the laser spot is shown in Figure 3, and the heat balance formula is:

in,

代表微元在x的负方向由于热传导流入的热量；

Represents the heat flowing into the micro-element in the negative direction of x due to thermal conduction;

代表微元在x的正方向由于热传导流入的热量；

Represents the heat flowing into the micro-element in the positive direction of x due to heat conduction;

代表微元在y的负方向由于热传导流入的热量；

Represents the heat flowing into the micro-element in the negative direction of y due to heat conduction;

代表微元在y的正方向由于热传导流入的热量；

Represents the heat flowing into the micro-element in the positive direction of y due to heat conduction;

where Δx and Δy represent the lengths of the micro-element in the x and y directions, respectively, λ _{(m, n)} represents the thermal conductivity of the micro-element, d represents the thickness of the sample, T _{(m-1, n)} and T _{(m+1 , n)} respectively represent the temperature of the two units before and after the micro-element in the x direction, T _{(m, n-1)} and T _{(m, n+1)} respectively represent the temperature of the two units before and after the micro-element in the y direction;

PΔxΔy represents the heat that the laser incident flows into the micro-element;

代表微元与周围环境的辐射换热，其中ε是实验之前确定的薄膜材料的发射率，σ是玻尔兹曼常数，T₀代表环境温度，考虑到薄膜的上下表面与周围环境都有辐射换热，因此乘2。

represents the radiative heat exchange between the micro-element and the surrounding environment, where ε is the emissivity of the film material determined before the experiment, σ is the Boltzmann constant, and T ₀ represents the ambient temperature, considering that the upper and lower surfaces of the film and the surrounding environment have radiation heat exchange, so multiply by 2.

Similarly, the heat balance equation outside the two-dimensional steady-state heat transfer spot can be written as

Combining the above equation and the temperature value of each point, λ _{(m, n)} at different positions can be obtained, and then corresponding to the temperature T _{(m, n)} at the position, the temperature of the film material at different temperatures can be obtained. Thermal conductivity λ _T .

In the same way, write out the heat balance equations inside and outside the two-dimensional transient heat transfer spot, respectively:

Within the spot

Outside the spot

代表在时间Δτ内微元由于温度上升引发的内能变化，a代表薄膜材料的热扩散系数，

和

分别代表下一时刻和该时刻该微元的温度值。结合上述方程，再加上前一阶段求出的导热系数λ,根据数值计算的方法就可以求得再不同温度下的热扩散系数a_T。in,

represents the change in internal energy of the micro-element due to temperature rise within the time Δτ, a represents the thermal diffusivity of the film material,

and

respectively represent the temperature value of the micro-element at the next moment and at this moment. Combined with the above equation and the thermal conductivity λ obtained in the previous stage, the thermal diffusivity a _T at different temperatures can be obtained according to the numerical calculation method.

S9. The driving mechanism drives the tensioning mechanism to control the sample 4 to generate a small displacement Δx (micrometer scale), and the sample 4 generates different strains. According to steps S2 to S4, the thermal conductivity and thermal diffusivity of the sample 4 under different strains are obtained. temperature changes. The thermal conductivity λ _T and thermal diffusivity a _T under different strains can be obtained by changing the amount of film strain.

The heat transfer of the silicon dioxide thin film is numerically solved using simulation software, and Figures 4 to 7 are obtained. As can be seen from Figure 6, when the temperature error range is ±1K, the thermal conductivity is only affected by ±2%; and when the thermal conductivity fluctuates within the range of ±10%, the temperature change caused is about 10K. It shows that the temperature is very sensitive to the change of thermal conductivity in this calculation method, and the error of the temperature is relatively small to the obtained thermal conductivity, which is beneficial to obtain accurate results.

The present invention has no requirement for electrical conductivity of the film material, and does not require a pretreatment process. It is only necessary to fix both ends of the sample to be tested for measurement, and the operation is convenient; the heating method of the present invention is non-contact, which reduces the contact thermal resistance. In addition, the vacuum environment is introduced to avoid the influence of convective heat transfer, and the accuracy and convenience of calculation are improved. the thermal conductivity and thermal diffusivity under different strains; the present invention generates different strains of the sample through the driving mechanism, and can measure the thermal physical parameters under different strains; the present invention uses laser heating, the output power of the laser is adjustable, and different thermal conductivity can be studied. Capability and thermal conductivity and thermal diffusivity of materials of different sizes at different temperature levels.

It should be understood that, for those skilled in the art, improvements or changes can be made according to the above description, and all these improvements and changes should fall within the protection scope of the appended claims of the present invention.

Claims (10)

1. A method for measuring the thermal conductivity and thermal diffusivity of a thin film material under strain is characterized in that: comprises the steps of (a) carrying out,

s1, spreading the sample, tensioning the sample by the tensioning mechanisms at two ends, placing the sample, the tensioning mechanism and the driving mechanism into a vacuum cavity, sealing and vacuumizing the vacuum cavity, and only considering heat conduction and heat radiation;

s2, heating the sample in the vacuum cavity by using continuous laser, and obtaining a temperature distribution diagram of the sample in the whole process from the beginning to the steady state under the fixed strain through an infrared camera;

s3, because the thickness of the film is far smaller than the side length, the film is regarded as two-dimensional heat transfer, the experimental picture is processed to obtain the temperature of each pixel point on the surface of the film, the film is divided into a plurality of micro-elements according to the size of the pixel point, and thus the temperature values of different micro-elements under fixed strain are obtained;

s4, establishing a steady-state and transient-state heat balance equation, and solving the heat conductivity coefficient and the heat diffusion coefficient of the film at different temperatures;

s5, the driving mechanism drives the tensioning mechanism, the sample is controlled to generate the micro displacement delta x, the sample generates different strains, and the conditions that the thermal conductivity and the thermal diffusivity of the sample change along with the temperature under different strains are obtained according to the steps S2 to S4.

2. The method of measuring thermal conductivity and thermal diffusivity of a thin film material under strain of claim 1 wherein:

in step S4, a steady state process is established

Established transient process

Wherein,

represents the heat of the micro element flowing in the negative direction of x due to heat conduction;

represents the heat quantity of the micro element flowing in the positive direction of x due to heat conduction;

represents the heat of the micro-element flowing in the negative direction of y due to heat conduction;

represents the heat quantity of the micro element flowing in the positive direction of y due to heat conduction;

where Δ x and Δ y represent the lengths of the infinitesimal elements in the x-and y-directions, respectively, and λ_(m，n)Represents the thermal conductivity of the micro-element, d represents the thickness of the sample, T_(m-1，n)And T_(m+1，n)Respectively representing the temperatures, T, of two units in front and behind the infinitesimal in the x direction_(m，n-1)And T_(m，n+1)Respectively representing the temperature of the front unit and the rear unit of the infinitesimal in the y direction;

p Δ x Δ y represents the amount of heat that the laser heats to flow into the infinitesimal element, wherein P is the incident intensity of the laser;

representing the radiative heat exchange between the upper and lower surfaces of the element and the surrounding environment, where ε is the emissivity of the sample, σ is the Boltzmann constant, and T is the emissivity of the sample_(m，n)Temperature, T, of the infinitesimal₀Representing the ambient temperature, considering that the upper and lower surfaces of the sample have radiation heat exchange with the surrounding environment,thus, multiply by 2;

represents the change of internal energy of the infinitesimal element caused by the temperature rise within the time delta tau, wherein

And

respectively, the temperature of the micro-element at the moment and the temperature of the micro-element at the later moment, and a represents the thermal diffusion coefficient of the film material.

3. The method of measuring thermal conductivity and thermal diffusivity of a thin film material under strain of claim 1 wherein: before measurement, the emissivity of the sample is determined, the surface temperature of the sample is measured by using the thermocouple, and the emissivity of the infrared camera is adjusted at the same time until the surface temperature measured by the infrared camera is the same as the temperature measured by the thermocouple, wherein the emissivity is the real emissivity of the sample.

4. A device for measuring the thermal conductivity and thermal diffusivity of a thin film material under strain is characterized in that: the device comprises a vacuum cavity with a light transmission window, a laser probe hermetically extending into the vacuum cavity, a laser connected with the laser probe, an air pump used for vacuumizing the vacuum cavity, an infrared camera for shooting a sample in the vacuum cavity facing the light transmission window, a data processing module connected with the infrared camera, a tensioning mechanism and a driving mechanism, wherein the tensioning mechanism is used for tensioning two ends of the sample, and the driving mechanism is used for driving the tensioning mechanism to control the sample to generate micro displacement.

5. The apparatus for measuring thermal conductivity and thermal diffusivity of thin film materials under strain of claim 4 wherein: the light-transmitting window adopts a germanium window.

6. The apparatus for measuring thermal conductivity and thermal diffusivity of thin film materials under strain of claim 4 wherein: the tensioning mechanism comprises two pairs of heat sinks which are flush and respectively positioned at two ends of the sample, and each pair of heat sinks clamps the end part of the sample from the upper side and the lower side and is fastened through a bolt.

7. The apparatus for measuring thermal conductivity and thermal diffusivity of thin film materials under strain of claim 6 wherein: the driving mechanism comprises a guide rail, a rack, a motor and a gear transmission system, wherein one pair of heat sinks are fixed in position, the lower heat sink of the other pair of heat sinks is in sliding fit with the guide rail, the upper heat sink of the other pair of heat sinks is fixed with the rack, the motor is meshed with the rack through the gear transmission system, and a power line of the motor hermetically extends out of the vacuum cavity and is connected with a power supply.

8. The apparatus for measuring thermal conductivity and thermal diffusivity of thin film materials under strain of claim 7 wherein: the gear transmission system comprises a motor output shaft, a pinion A arranged on the motor output shaft, a fixed shaft, and a bull gear B and a pinion C arranged on the fixed shaft, wherein the pinion A is meshed with the bull gear B, and the pinion C is meshed with a rack.

9. The apparatus for measuring thermal conductivity and thermal diffusivity of thin film materials under strain of claim 8 wherein: sample stretching amount generated by single pulse when the motor is a stepping motor

Wherein r is_A、r_BAnd r_CRepresents radii of gear A, gear B and gear C, θ₀Representing the pitch angle of the motor.

10. The apparatus for measuring thermal conductivity and thermal diffusivity of thin film materials under strain of claim 4 wherein: the laser probe is obliquely incident on the sample.

Images