Method and system for measuring thermal distribution of power devices with time and space resolution

Abstract

The present invention discloses a method and system for measuring the thermal distribution of a power device with time and space resolution. The method includes the following steps: calibrating the temperature-Raman shift coefficient of the power device to be measured; based on the calibrated temperature-Raman shift coefficient, measuring the temperature distribution with time and space resolution of the power device in a pulsed operating state. The present invention provides a method for measuring the thermal distribution of a power device with time and space resolution to solve the technical problem in the prior art that the temperature distribution of a power device with space resolution and time resolution cannot be measured simultaneously. This method can measure the thermal distribution of a power device with high space resolution and time resolution in a non-contact manner.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical temperature measurement, and particularly relates to a method and system for measuring the thermal distribution of a power device with time and space resolution. Background Art

[0002] The temperature of semiconductor power devices has a great influence on the performance and reliability of the devices. With the reduction of the size of power devices and the increase of the operating frequency, the influence brought by the thermal effect cannot be ignored any more. Although using high-thermal-conductivity materials and external heat dissipation and other means can reduce the influence of excessive temperature to a certain extent, this problem cannot be fundamentally improved. Therefore, only by fully considering the thermal effect in the device design process can this problem be fundamentally changed. However, for the semiconductor power device chips that have been integrated and packaged, the measurement of the operating temperature usually can only detect the whole chip when the device is working, it is very difficult to distinguish the temperature of a single device, and it is also very difficult to distinguish the specific heating time.

[0003] The Raman spectroscopy temperature measurement method has received extensive attention and application due to its advantages such as high spatial resolution and non-damage to samples. This technology uses an optical microscope to focus a laser beam on the device to be measured. Photons interact with the semiconductor material in the device, exciting various scattering signals. A spectrometer is used to collect the Stokes-Raman scattering and anti-Stokes-Raman scattering signals among them, and the temperature of the material is obtained according to the temperature dependence of the Raman scattering phonon frequency.

[0004] For semiconductor power devices, especially wide-bandgap semiconductor devices, the changes in the temperature magnitude and temperature distribution during the on-state and off-state processes are a very worthy part of attention, which helps to increase the understanding of the device working mechanism. However, there is currently no method that can simultaneously measure the spatially resolved and time-resolved temperature distributions of semiconductor devices. How to simultaneously realize the measurement of the temperature distribution of power devices with spatial resolution and time resolution has become a difficult problem to be solved urgently. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and system for measuring the thermal distribution of a power device with time and space resolution to solve one or more of the above-mentioned technical problems. Specifically, in order to solve the technical problem that the temperature distribution of a power device with spatial resolution and time resolution cannot be measured simultaneously in the prior art, the present invention provides a method for measuring the thermal distribution of a power device with time and space resolution. This method can measure the thermal distribution of a power device with high spatial resolution and time resolution in a non-contact form.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for measuring the thermal distribution of a power device with time and space resolution provided by the present invention includes the following steps:

[0008] Calibrate the temperature-Raman shift coefficient of the power device to be measured;

[0009] Based on the calibrated temperature-Raman shift coefficient, measure the temperature distribution with time and space resolution of the power device under pulsed operating conditions;

[0010] Among them, the step of measuring the temperature distribution with time and space resolution of the power device under pulsed operating conditions includes:

[0011] At room temperature, apply a high-frequency electrical pulse signal with a pulse width t e and an interval t c . Keep the pulsed laser synchronized with the electrical pulse signal. When the gate voltage is less than the threshold voltage of the power device to be measured, use the pulsed laser to detect the power device to be measured, and obtain the first Raman shift at room temperature for all measurement points in the preset target space;

[0012] At room temperature, apply a high-frequency electrical pulse signal with a pulse width t e and an interval t c . Keep the pulsed laser synchronized with the electrical pulse signal. The delay between the pulsed laser and the electrical pulse signal is t d . When the gate voltage is greater than or equal to the threshold voltage of the power device to be measured, use a pulsed laser with a pulse width of t p to detect the power device to be measured, and obtain the Raman shift under pulsed operating conditions for all measurement points in the preset target space at the delay time t d ;

[0013] For each measurement point in the preset target space, calculate the transient temperature of the measurement point at the delay time t d based on the first Raman shift at room temperature, the Raman shift under pulsed operating conditions, and the temperature-Raman shift coefficient. Adjust the delay time based on the preset delay time increment step size to obtain the temperature distribution with time and space resolution of the power device.

[0014] A further improvement of the method of the present invention is that during the process of calibrating the temperature-Raman shift coefficient of the power device to be measured, the temperature interval is greater than or equal to 5°C; the temperature calibration range is from room temperature to 300°C.

[0015] A further improvement of the method of the present invention is that the laser power of the pulsed laser is less than or equal to 1 W; the pulse width t e of the electrical pulse signal is greater than the pulse width t p of the pulsed detection laser.

[0016] A further improvement of the method of the present invention lies in that the step of measuring the time- and space-resolved temperature distribution of the power device in the pulsed operating state specifically includes:

[0017] For any measurement point (x m , y n ) within the preset target space, when the gate voltage is less than the threshold voltage of the power device to be measured, a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain. Keeping the pulsed laser synchronized with the electrical pulse signal, the power device to be measured is detected using the pulsed laser, and the Raman shift w m , y n ) at room temperature T r is obtained; mn ;

[0018] For the measurement point (x m , y n ), when the gate voltage is greater than or equal to the threshold voltage of the power device to be measured, a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain. Keeping the pulsed laser synchronized with the electrical pulse signal, the delay between the pulsed laser and the electrical pulse signal is t d . The power device to be measured is detected using the pulsed laser, and the Raman shift w d1 at the pulsed operating state and delay time t mn (t d1 ) is obtained;

[0019] Based on the Raman shift w mn , the pulsed operating state, the Raman shift w d1 at the delay time t mn (t d1 ) and the temperature-Raman shift coefficient k, the transient temperature T(x m , y n ) at the delay time t d1 of the measurement point (x m , y n , t d1 ) is calculated;

[0020] For the measurement point (x m , y n ), the delay time is increased in steps of t step through the signal generator, and the steps of obtaining the transient temperature are repeated until the transient temperature T(x dn , y m , t n ) at the delay time t dn is obtained;

[0021] Combining the transient temperatures at different delay times, the time-resolved transient temperature T(x m , y n ) at the measurement point within the working interval from t d1 to t dn is obtained; m , y n , t);

[0022] Among them, for the transient temperature the delay time t d1 is less than the sum of the pulse width t e and the pulse interval t c ; for the transient temperature the delay time t dn is less than the repetition frequency of the electrical pulse signal; the delay time t dn = t d1 + (n - 1) × t step , where n is any natural number; the step size of the increase in the delay time is greater than or equal to the pulse width t p of the pulsed probe laser;

[0023] The transient temperature T(x m , y n , t) = {T(x m , y n , t d1 ), T(x m , y n , t d2 ), ……, T(x m , y n , t dn )}.

[0024] A further improvement of the method of the present invention is that it further includes the following steps:

[0025] Based on the calibrated temperature-Raman shift coefficient, the spatially resolved temperature distribution of the power device is measured under the DC working state.

[0026] A further improvement of the method of the present invention is that the step of measuring the spatially resolved temperature distribution of the power device under the DC working state includes:

[0027] At room temperature, when the gate voltage is less than the threshold voltage of the power device to be measured and a DC bias voltage is applied, the power device to be measured is probed with a continuous laser to obtain the second Raman shift at room temperature at all measurement points in the preset target space;

[0028] At room temperature, when a DC bias voltage is applied, the power device to be measured is probed with a continuous laser to obtain the Raman shift under the DC working state at all measurement points in the preset target space;

[0029] For each measurement point in the preset target space, the steady-state temperature is calculated based on the Raman shift at the second room temperature, the Raman shift in the flowing working state, and the temperature-Raman shift coefficient, and the temperature distribution with spatial resolution of the power device is obtained.

[0030] A measurement system for the thermal distribution of a power device with time and spatial resolution provided by the present invention includes:

[0031] A calibration module for calibrating the temperature-Raman shift coefficient of the power device to be measured;

[0032] A first temperature distribution acquisition module for measuring and obtaining the temperature distribution with time and spatial resolution of the power device based on the calibrated temperature-Raman shift coefficient in the pulsed working state;

[0033] Among them, the step of measuring and obtaining the temperature distribution with time and spatial resolution of the power device in the pulsed working state includes:

[0034] At room temperature, a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain, the pulsed laser is kept synchronized with the electrical pulse signal, and in the case where the gate voltage is less than the threshold voltage of the power device to be measured, the power device to be measured is detected by the pulsed laser to obtain the first Raman shift at room temperature of all measurement points in the preset target space;

[0035] At room temperature, a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain, the pulsed laser is kept synchronized with the electrical pulse signal, the delay between the pulsed laser and the electrical pulse signal is t d , and in the case where the gate voltage is greater than or equal to the threshold voltage of the power device to be measured, the power device to be measured is detected by a pulsed laser with a pulse width of t p to obtain the Raman shift in the pulsed working state of all measurement points in the preset target space at the delay time t d ;

[0036] For each measurement point in the preset target space, the transient temperature of the measurement point at the delay time t d is calculated based on the first Raman shift at room temperature, the Raman shift in the pulsed working state, and the temperature-Raman shift coefficient, and the delay time is adjusted based on the preset delay time increase step size to obtain the temperature distribution with time and spatial resolution of the power device.

[0037] A further improvement of the system of the present invention lies in that the step of measuring and obtaining the temperature distribution with time and spatial resolution of the power device in the pulsed working state specifically includes

[0038] For any measurement point (x m , yn ), the gate voltage is less than the threshold voltage of the power device to be measured, and a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain. Keep the pulsed laser synchronized with the electrical pulse signal, and use the pulsed laser to detect the power device under measurement to obtain the Raman shift w m at the measurement point (x n ) at room temperature T r ; mn ;

[0039] For the measurement point (x m , y n ), the gate voltage is greater than or equal to the threshold voltage of the power device to be measured, and a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain. Keep the pulsed laser synchronized with the electrical pulse signal, and the delay between the pulsed laser and the electrical pulse signal is t d . Use the pulsed laser to detect the power device under measurement to obtain the Raman shift w d1 at the pulsed operating state and delay time t mn (t d1 );

[0040] Based on the Raman shift w mn , the pulsed operating state, and the Raman shift w d1 at the delay time t mn (t d1 ) and the temperature-Raman shift coefficient k, calculate the transient temperature T(x m , y n ) at the measurement point (x d1 , y m , y n , t d1 ) at the delay time t

[0041] For the measurement point (x m , y n ), increase the delay time in steps of t step through the signal generator, and repeat the steps of obtaining the transient temperature until the transient temperature T(x dn , y m , y n , t dn ) at the delay time t

[0042] Combine the transient temperatures at different delay times to obtain the time-resolved transient temperature T(x m , y n ) at the measurement point (x d1 to t dn within the working interval t m , yn , t);

[0043] Among them, the transient temperature The delay time t d1 is less than the pulse width t e and the pulse interval t c ; The transient temperature The delay time t dn is less than the repetition frequency of the electrical pulse signal; The delay time t dn = t d1 + (n - 1) × t step , where n is any natural number; The increasing step of the delay time is greater than or equal to the pulse width t of the pulsed probing laser p ;

[0044] The transient temperature T(x m , y n , t) = {T(x m , y n , t d1 ), T(x m , y n , t d2 ), ……, T(x m , y n , t dn )}.

[0045] A further improvement of the system of the present invention lies in that it further includes:

[0046] A second temperature distribution acquisition module, configured to measure and obtain the spatially resolved temperature distribution of the power device in the DC working state based on the calibrated temperature - Raman shift coefficient.

[0047] A further improvement of the system of the present invention is that the step of measuring and obtaining the spatially resolved temperature distribution of the power device in the DC working state includes:

[0048] At room temperature, when the gate voltage is less than the threshold voltage of the power device to be measured and a DC bias voltage is applied, use a continuous laser to probe the power device to be measured to obtain the second Raman shift at room temperature of all measurement points in the preset target space;

[0049] At room temperature, when a DC bias voltage is applied, use a continuous laser to probe the power device to be measured to obtain the Raman shift in the DC working state of all measurement points in the preset target space;

[0050] For each measurement point in the preset target space, calculate the steady - state temperature based on the second Raman shift at room temperature, the Raman shift in the DC working state, and the temperature - Raman shift coefficient, and obtain the spatially resolved temperature distribution of the power device.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The measurement method of the thermal distribution of a power device with time and space resolution provided by the present invention, on the premise of meeting the functions of the existing Raman temperature measurement method applied to power devices, based on the relationship between Raman shift and temperature, uses the method of synchronizing the pulsed laser detection signal with the electrical pulse signal, and can simultaneously measure the thermal distribution of the power device with space and time resolution, which is beneficial for further understanding the device working mechanism and improving the device structure design. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the description of the embodiments or the prior art; obviously, the drawings in the following description are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0054] Figure 1 is a schematic flow chart of a measurement method for the thermal distribution of a power device with time and space resolution according to an embodiment of the present invention;

[0055] Figure 2 is a schematic flow chart of another measurement method for the thermal distribution of a power device with time and space resolution according to an embodiment of the present invention;

[0056] Figure 3 is a schematic diagram of the test state of a multi-finger gate power device in an embodiment of the present invention;

[0057] Figure 4 is a schematic diagram of the change in the temperature-Raman shift relationship of the gallium nitride epitaxial layer material of the device to be tested in an embodiment of the present invention;

[0058] Figure 5 is a schematic diagram of the change in the temperature-Raman shift relationship of the diamond material of the device to be tested in an embodiment of the present invention;

[0059] Figure 6 is a schematic diagram of the temperature distribution in an embodiment of the present invention;

[0060] Figure 7 is a schematic diagram of the sequence of the electrical pulse signal and the pulsed detection laser, and the change in the temperature of the device to be tested in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0061] To enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0062] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0063] The present invention will be further described in detail below in conjunction with the accompanying drawings:

[0064] Please refer to Figure 1 , a method for measuring the thermal distribution of a power device with time and space resolution in an embodiment of the present invention, includes the following steps:

[0065] Calibrate the temperature-Raman shift coefficient of the power device to be measured;

[0066] Based on the calibrated temperature-Raman shift coefficient, measure the spatially resolved temperature distribution of the power device under the DC working state;

[0067] Based on the calibrated temperature-Raman shift coefficient, measure the temporally and spatially resolved temperature distribution of the power device under the pulsed working state;

[0068] Among them, the step of measuring the spatially resolved temperature distribution of the power device under the DC working state specifically includes:

[0069] At room temperature, when the gate voltage is less than the threshold voltage (exemplary and can be determined according to the power device to be measured) and a DC bias voltage is applied, use a continuous laser to detect the power device to be measured, and obtain the Raman shift at room temperature of all measurement points in a preset target space (exemplary, which can be the channel position of the power device to be measured);

[0070] At room temperature, with a DC bias voltage applied, a continuous laser is used to detect the power device to be measured, and the Raman shift under the DC operating state of all measurement points in the preset target space is obtained.

[0071] For each measurement point in the preset target space, based on the Raman shift at room temperature, the Raman shift under the DC operating state, and the temperature-Raman shift coefficient, the steady-state temperature is calculated and obtained.

[0072] Among them, the specific steps for measuring the time- and space-resolved temperature distribution of the power device under the pulsed operating state include:

[0073] At room temperature, when the gate voltage is less than the threshold voltage, a pulsed laser is used to detect the power device to be measured, and the Raman shift at room temperature of all measurement points in the preset target space is obtained.

[0074] At room temperature, a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain. The pulsed laser is kept synchronized with the electrical pulse signal, and the delay between the pulsed laser and the electrical pulse signal is t d . A pulsed laser with a pulse width of t d is used to detect the power device to be measured, and the Raman shift under the pulsed operating state of all measurement points in the preset target space at the delay time of t p is obtained. p At room temperature, a pulsed laser with a pulse width of t d is used to detect the power device to be measured, and the Raman shift under the pulsed operating state of all measurement points in the preset target space at the delay time of t d is obtained.

[0075] For each measurement point in the preset target space, based on the Raman shift at room temperature, the Raman shift under the pulsed operating state, and the temperature-Raman shift coefficient, the transient temperature of the measurement point at the delay time of t d is calculated. Based on the preset step size for increasing the delay time, the delay time is adjusted to obtain the transient temperature distribution. d

[0076] The measurement method for the thermal distribution of a power device with time and space resolution proposed in the embodiments of the present invention includes: calibrating the temperature-Raman shift coefficient of the sample; when the device is in the high-frequency operating state, using a pulsed laser synchronized with the operating voltage of the device, changing the delay time and the spot position, and measuring the thermal distribution with space and time resolution, which solves the problem that the general measurement method cannot simultaneously obtain the thermal distribution of a power device with space and time resolution, and has beneficial effects for further understanding the high-temperature failure mechanism of the power device and improving the thermal design of the device.

[0077] Exemplarily and preferably in the embodiments of the present invention, during the calibration process of the temperature-Raman shift coefficient k, it is necessary to ensure that the temperature interval is at least 5°C; the temperature calibration range needs to be from room temperature T r to 200°C; k = dw / dT. In addition, the laser used for detection is a pulsed laser, and the laser power is not greater than 1 W. Furthermore, the repetition frequencies of the electrical pulse signal and the pulsed detection laser are the same, and the pulse width t of the electrical pulse signale Greater than the pulse width t of the pulsed probe laser p .

[0078] Please refer to Figure 2 , a measurement method for the thermal distribution of a power device with time and spatial resolution according to an embodiment of the present invention, includes the following steps:

[0079] 1. Perform Raman spectroscopy tests on the sample to be measured at different temperatures, and calibrate the temperature-Raman shift coefficient k;

[0080] 2. Under the DC working state, measure the spatially resolved temperature distribution of the power device, including:

[0081] 2.1. At room temperature T r , when in the off state, use a continuous laser to detect the sample, and obtain the Raman shift w of the power device to be measured at the initial position (x1, y1) at room temperature 11 ;

[0082] 2.2. At room temperature T r , apply a DC bias voltage to the drain, use a continuous laser to detect the sample, and obtain the Raman shift w' of the power device to be measured at the initial position (x1, y1) under the DC working state 11 ;

[0083] 2.3. Combine the Raman shift w 11 at the initial position (x1, y1) at room temperature, the Raman shift w' 11 under the DC working state, and the temperature-Raman shift coefficient k, and calculate the steady-state temperature T(x1, y1) of the current measurement point (x1, y1) under the DC working state;

[0084] 2.4. By moving the mechanical sample stage, adjust the position of the center of the continuous detection laser spot on the sample to any measurement point (x m , y n ) within the space to be measured, repeat the test method of the measurement point (x1, y1), and obtain the steady-state temperature T(x m , y n ) of the measurement point (x m , y n ) under the DC working state;

[0085] 2.5. Select an appropriate moving step of the sample stage, repeat the above process, and obtain the steady-state spatial temperature distribution T(x, y) under the DC working state.

[0086] Among them, the steady-state temperature

[0087] Among them, the steady-state temperature distribution

[0088] 3. Measurement of the time- and space-resolved temperature distribution of power devices in the pulsed operating state, including:

[0089] 3.1 At room temperature \(T\) r When in the off state, the sample is probed using a pulsed laser to obtain the Raman shift \(w\) at room temperature at the initial position \((x1, y1)\) of the device under test. 11 ;

[0090] 3.2 At room temperature \(T\) r A high-frequency electrical pulse signal with a pulse width \(t\) e and a pulse interval \(t\) c is applied to the drain. The pulsed laser is synchronized with the electrical pulse signal, and the delay between the pulsed laser and the electrical pulse signal is \(t\) d1 . A pulsed laser with a pulse width of \(t\) p is used to probe the power device under test, and the Raman shift \(w\) d at the initial position \((x1, y1)\) in the pulsed operating state and at a delay time \(t\) 11 \((t\) d ) is obtained.

[0091] 3.3 Combining the Raman shift \(w\) 11 at room temperature at the initial position \((x1, y1)\), the pulsed operating state, and the Raman shift \(w\) d1 at a delay time \(t\) 11 \((t\) d1 ) and the temperature-Raman shift coefficient \(k\), the instantaneous temperature \(T(x1, y1, t\) d1 at the measurement point \((x1, y1)\) at the delay time \(t\) d1 ) is calculated.

[0092] 3.4 The delay time is increased in steps of \(t\) step using a signal generator, and the test steps at a delay time of \(t\) d1 are repeated until the transient temperature \(T(x1, y1, t\) dn ) at the delay time \(t\) dn is obtained.

[0093] 3.5 Combining the transient temperatures at different delay times, the time-resolved transient temperature \(T(x1, y1, t)\) within the operating interval \(t\) d1 to \(t\) dn at the initial measurement point \((x1, y1)\) is obtained.

[0094] 3.6 By moving the mechanical sample stage, the center of the pulsed probing laser spot on the sample is adjusted to any measurement point \((x\) m , y n ) within the space to be measured. The test steps for the measurement point \((x1, y1)\) are repeated to obtain the measurement point \((x\) m, y n ) transient temperature T(x m , y n , t);

[0095] 3.7. Select an appropriate moving step of the sample stage and repeat the above process to obtain a temperature distribution T(x, t, t) with time and space resolution.

[0096] Among them, the transient temperature delay time t d1 is less than the pulse width t e and the pulse interval t c The sum is the repetition frequency of the electrical pulse signal.

[0097] Among them, the transient temperature delay time t dn is less than the repetition frequency of the electrical pulse signal.

[0098] Among them, the delay time t dn = t d1 + (n - 1) × t step , where n is any natural number.

[0099] Among them, the increasing step of the delay time is not less than the pulse width t of the pulsed probe laser p .

[0100] Among them, the transient temperature T(x1, y1, t) = {T(x1, y1, t d1 ), T(x1, y1, t d2 ), ……, T(x1, y1, t dn )}.

[0101] Among them, the transient temperature T(x m , y n , t) = {T(x m , y n , t d1 ), T(x m , y n , t d2 ), ……, T(x m , y n , t dn )}.

[0102] Among them, the temperature distribution Specific Example 1:

[0104] Please refer to Figure 3 , Figure 4 , Figure 6 and Figure 7, the following description is a non - restrictive example of temperature measurement for a gallium nitride power semiconductor device, specifically including the following steps:

[0105] Step 1, determine the temperature - Raman shift coefficient of the semiconductor material in the device under test. After removing the package of the device under test 201, it is fixed on the temperature - variable stage 202. Here, the device under test 201 is a gallium nitride power semiconductor device. Set the initial temperature of the temperature - variable stage to 25 °C, and the continuous probing laser 101 is focused on the surface of the device under test. The wavelength of the probing laser is 532 nm. The scattered signal 102 undergoes filtering and spectral splitting processes, and the Raman scattering signal is collected and measured by a spectrometer to obtain the Raman spectrum corresponding to 25 °C, which contains the E2(H) peak of the GaN epitaxial material. Change the temperature of the temperature - variable stage 202 (increase by 10 °C each time) and stabilize for half an hour, repeat the above process, and measure the temperature - Raman shift change curve of the E2(H) peak of the gallium nitride epitaxial material. As Figure 4 shown, the slope of this curve is the temperature - Raman shift relationship, k = dw / dT ≈ - 0.02 cm -1 / K;

[0106] Step 2, spatially resolved thermal distribution measurement. Keep the temperature of the temperature - variable stage 202 fixed at 25 °C, and the continuous probing laser is focused on the surface position (x1, y1) of the device under test 201. When the drain bias 103 is 5 V and the gate bias is - 5 V (threshold voltage is - 3.5 V), set the initial temperature of the temperature - variable stage 202 to 25 °C and stabilize for half an hour. At this time, the Raman spectrum is the Raman spectrum of 25 °C at (x1, y1), and read the Raman shift w 11 of the E2(H) peak of the GaN epitaxial material. Through the mechanical platform 203, adjust the position of the laser spot on the device under test 201 in the Y - direction with a step size of 0.5 μm, and measure the Raman spectrum of 25 °C at (x m , y n ) and read the Raman shift w mn of the E2(H) peak.

[0107] Change the DC bias voltage of the drain bias 103 to 5 V, the source is grounded, and the gate bias voltage is 0 V. Wait for 5 minutes to make the temperature distribution of the device under test 201 reach a steady state. Through the mechanical platform 203, reset the spot position of the probing laser 101 back to (x1, y1), and measure and read the Raman spectrum and Raman shift w′ 11 at the initial position (x1, y1). With a step size of 0.5 μm, adjust the position of the laser spot in the Y - direction, and measure and read the Raman spectra and Raman shifts w′ m , y n ) at different positions. mn .

[0108] Combined with the temperature-Raman shift relationship k of the E2(H) peak of the gallium nitride epitaxial material, the spatially resolved thermal distribution T(x,y) is obtained through the formula where T r is 25 °C. Figure 6 This is the thermal distribution with high spatial resolution of the gallium nitride power semiconductor device measured in this embodiment.

[0109] Step 3, measurement of time- and space-resolved thermal distribution. Figure 7 This is the sequence of the electrical pulse signal and the pulsed probe laser in the embodiment, as well as the schematic diagram of the temperature change of the device under test. The temperature of the temperature control stage 202 is fixed at 25 °C and stabilized for 30 min. The probe laser 101 is focused on the surface position (x1,y1) of the device under test 201. The probe laser is a pulsed laser with a pulse width t p of 50 ns and a period of 1 μs. A pulsed bias voltage of 5 V is applied to the drain 103. When the gate bias voltage is -5 V (the threshold voltage is -3.5 V), the Raman spectrum at (x1,y1) is measured, and the Raman shift w of the E2(H) peak of the GaN epitaxial material is read 11 . Through the mechanical stage 203, the position of the laser spot on the device under test 201 is adjusted in the x direction with a step size of 0.5 μm, and the above process is repeated. At the same time, the Raman spectra and Raman shifts w at 25 °C at different positions (x m ,y n ) are stored mn .

[0110] The pulsed bias voltage of the drain bias 103 is 5 V, the pulse width is t e of 500 ns, the period is 1 μs, the source is grounded, and the gate bias voltage is 0 V. The drain bias 103 is synchronized with the probe laser 101, and the initial delay between them is t d . The temperature of the temperature control stage 202 is fixed at 25 °C. The mechanical stage 203 is adjusted so that the probe laser 101 is focused on the initial position (x1,y1). The time delay t d is 0 s. The Raman spectrum and Raman shift w at (x1,y1) at a time delay of 0 s are measured and read 11 (0). The delay time t d is gradually increased with a step size of 50 ns. The Raman spectra and Raman shifts w at different time delays t d are measured and recorded 11 (t d ).

[0111] The mechanical stage 203 is adjusted to adjust the spot position of the probe laser 101 in the Y direction with a step size of 0.5 μm, and the delay time t d is adjusted. The Raman spectra and Raman shifts at different positions (x m ,yn ) and different delay times t d Raman spectra and Raman shifts w mn (t d ).

[0112] Combined with the temperature-Raman shift relationship k of the E2(H) peak of the gallium nitride epitaxial material, the time- and space-resolved thermal distribution T(x, y, t) is obtained through the formula where T r is 25 °C. Specific Example 2:

[0114] Please refer to Figure 3 , Figure 5 and Figure 7 The following description is a non-limiting example of the temperature measurement of a diamond-based power semiconductor device, specifically including the following steps:

[0115] Step 1, determine the temperature-Raman shift coefficient of the semiconductor material in the device to be measured. After removing the package of the device to be measured 201, it is fixed on the temperature-variable stage 202, where the device to be measured 201 is a diamond-based power semiconductor device. Set the initial temperature value of the temperature-variable stage to 25 °C, and the continuous probing laser 101 is focused on the surface of the device to be measured, as Figure 3 shown. The wavelength of the probing laser is 532 nm. The scattered signal 102 is filtered and spectroscopically analyzed, and the Raman scattering signal is collected and measured by a spectrometer to obtain the Raman spectrum corresponding to 25 °C, which contains the Raman peaks of the diamond material. Change the temperature of the temperature-variable stage 202 (increase by 10 °C each time) and stabilize for half an hour, repeat the above process, and measure the temperature-Raman shift change curve of the diamond Raman peak, as Figure 5 shown. The slope of this curve is the temperature-Raman shift relationship, that is

[0116] k1 = dw / dT ≈ -0.0124 cm -1 / K;

[0117] k2 = dw / dT ≈ -0.0286 cm -1 / K;

[0118] Step 2, spatially resolved thermal distribution measurement. Fix the temperature of the temperature-variable stage 202 at 25°C, and continuously detect the laser focused at the surface position (x1, y1) of the device under test 201. When the drain bias 103 is 5V and the gate bias is -5V (threshold voltage is -3.5V), set the initial temperature of the temperature-variable stage 202 to 25°C and stabilize for half an hour. At this time, the Raman spectrum is the Raman spectrum at 25°C at (x1, y1). Read the Raman shift w1 of the diamond Raman peak. Through the mechanical stage 203, adjust the position of the laser spot on the device under test 201 in the Y direction with a step size of 0.1μm, and measure the Raman spectrum at 25°C at (x m ,y n ) and read the Raman shift w mn .

[0119] Change the DC bias voltage of the drain bias 103 to 5V, ground the source, and set the gate bias voltage to 0V. Wait for 5 minutes to make the temperature distribution of the device under test 201 reach a steady state. Through the mechanical stage 203, reset the spot position of the detection laser 101 back to (x1, y1), and measure and read the Raman spectrum and Raman shift w′ at the initial position (x1, y1) 11 . With a step size of 0.1μm, adjust the position of the laser spot in the Y direction, and measure and read the Raman spectra and Raman shifts w′ at different positions (x m ,y n ). n .

[0120] Combined with the temperature-Raman shift relationship k of the diamond Raman peak, obtain the spatially resolved thermal distribution T(x, y) through the formula , where T r is 25°C.

[0121] Step 3, time- and spatially resolved thermal distribution measurement. Figure 7 is the sequence of the electrical pulse signal and the pulsed detection laser in the embodiment, as well as the schematic diagram of the temperature change of the device under test. Fix the temperature of the temperature-variable stage 202 at 25°C and stabilize for 30 min. The detection laser 101 is focused at the surface position (x1, y1) of the device under test 201. The detection laser is a pulsed laser, and the pulse width t p is 10 ns and the period is 500 ns. When a pulsed bias voltage of 5V is applied to the drain 103 and the gate bias is -5V (threshold voltage is -3.5V), measure the Raman spectrum at (x1, y1) and read the Raman shift w 11 . Through the mechanical stage 203, adjust the position of the laser spot on the device under test 000 in the x direction with a step size of 0.1μm, and repeat the above process while storing the Raman spectra at different positions (x m ,y n) Raman spectrum and Raman shift w at 25 °C mn 。

[0122] The drain bias 103 is a pulsed bias voltage of 5 V, the pulse width is t e is 250 ns, the period is 500 ns, the source is grounded, and the gate bias voltage is 0 V. The drain bias 103 is synchronized with the probe laser 101, and the delay between them is t d 。The temperature of the variable temperature stage 202 is fixed at 25 °C, and the mechanical stage 203 is adjusted so that the probe laser 101 is focused at the initial position (x1, y1), and the time delay t d is 0 s, and the Raman spectrum and Raman shift w at (x1, y1) at a time delay of 0 s are measured and read 11 (0). Increase the delay time t d , with a step size of 10 ns, measure and record the Raman spectra and Raman shifts w d at different time delays t 11 (t d ).

[0123] Adjust the mechanical stage 203, with a step size of 0.1 μm, to adjust the spot position of the probe laser 101 in the Y direction, and adjust the delay time t d , measure and record the Raman spectra and Raman shifts w at different positions (x m , y n ) and different delay times t d . mn (t d ).

[0124] Combined with the temperature-Raman shift relationship k of the diamond Raman peak, the time- and space-resolved thermal distribution T(x, y, t) is obtained through the formula , where T r is 25 °C. Specific Example 3:

[0126] Please refer to Figure 3 and Figure 7 , the following description is a non-limiting example of temperature measurement of a silicon-based power semiconductor device, specifically including the following steps:

[0127] Step 1, determine the temperature-Raman shift coefficient of the semiconductor material in the device under test. After removing the package of the device under test 201, it is fixed on the variable temperature stage 202. Here, the device under test 201 is a silicon-based power semiconductor device. Set the initial temperature value of the variable temperature stage to 25 °C, and continuously focus the probe laser 101 on the surface of the device under test, such as Figure 3As shown, the wavelength of the probing laser is 532 nm. The scattered signal 102 is subjected to filtering and spectral splitting. The Raman scattered signal is collected and measured by a spectrometer to obtain the Raman spectrum corresponding to 25 °C, which contains Raman shift peaks that are the Raman peaks of single-crystalline silicon. The temperature of the temperature-variable stage 202 is changed (increasing by 10 °C each time) and stabilized for half an hour, and the above process is repeated to measure the change curve of the temperature-Raman shift of the silicon Raman peak. The slope of this curve is the temperature-Raman shift relationship k = dw / dT.

[0128] Step two, measurement of spatially resolved thermal distribution. Fix the temperature of the temperature-variable stage 202 at 25 °C, and focus the continuous probing laser on the surface position (x1, y1) of the device under test 201. When the drain bias 103 is 0 V, set the initial temperature value of the temperature-variable stage 202 to 25 °C and stabilize for half an hour. At this time, the Raman spectrum is the Raman spectrum of 25 °C at (x1, y1), and read the Raman shift w of the silicon Raman peak. 11 . Through the mechanical platform 203, adjust the position of the laser spot on the device under test 201 in the Y direction with a step size of 0.5 μm, and measure the Raman spectrum of 25 °C at (x m , y n ) and read the Raman shift w of the silicon Raman peak. mn .

[0129] Change the drain bias 103 to a DC bias voltage of 5 V, ground the source, and set the gate bias voltage to 0 V. Wait for 5 minutes to make the temperature distribution of the device under test 201 reach a steady state. Through the mechanical platform 203, reset the spot position of the probing laser 101 back to (x1, y1), and measure and read the Raman spectrum and Raman shift w′ at the initial position (x1, y1). 11 . With a step size of 0.5 μm, adjust the position of the laser spot in the Y direction, and measure and read the Raman spectra and Raman shifts w′ at different positions (x m , y n ). mn .

[0130] Combined with the temperature-Raman shift relationship k of the silicon Raman peak, the spatially resolved thermal distribution T(x, y) is obtained through the formula , where T r is 25 °C.

[0131] Step three, measurement of time- and space-resolved thermal distribution. Figure 7 is the sequence of the electrical pulse signal and the pulsed probing laser in the embodiment, as well as the schematic diagram of the temperature change of the device under test. Fix the temperature of the temperature-variable stage 202 at 25 °C and stabilize for 30 min. Focus the probing laser 101 on the surface position (x1, y1) of the device under test 201. The probing laser is a pulsed laser, and the pulse width t pis 50 ns, and the period is 1 μs. When the drain bias 103 is 0 V, the Raman spectrum of (x1, y1) is measured, and the Raman shift w of the silicon Raman peak is read 11 . Through the mechanical platform 203, the position of the laser spot on the device under test 201 to be measured is adjusted in the x direction with a step size of 0.5 μm, and the above process is repeated while storing the Raman spectra and Raman shifts w at different positions (x m , y n ) at 25 °C mn .

[0132] The pulsed bias voltage with the drain bias 103 being 5 V, the pulse width is t e is 500 ns, the period is 1 μs, the source is grounded, and the gate bias voltage is 0 V. The drain bias 103 is synchronized with the probe laser 101, and the initial delay between the two is t d . The temperature of the temperature-variable stage 202 is fixed at 25 °C. The mechanical platform 203 is adjusted to focus the probe laser 101 at the initial position (x1, y1), and the time delay t d is 0 s. The Raman spectrum and Raman shift w at (x1, y1) at a time delay of 0 s are measured and read 11 (0). The delay time t d is gradually increased with a step size of 50 ns, and the Raman spectra and Raman shifts w at different time delays t d are measured and recorded 11 (t d ).

[0133] The mechanical platform 203 is adjusted to adjust the spot position of the probe laser 101 in the Y direction with a step size of 0.5 μm, and the delay time t d is adjusted. The Raman spectra and Raman shifts w at different positions (x m , y n ) and different delay times t d are measured and recorded mn (t d ).

[0134] Combined with the temperature-Raman shift relationship k of the silicon Raman peak, the time- and space-resolved thermal distribution T(x, y, t) is obtained through the formula , where T r is 25 °C

[0135] Based on the above specific embodiments, a measurement method for the thermal distribution of a power device with time and space resolution proposed by the present invention can accurately measure the planar spatial temperature distribution of existing main types of power devices under DC and pulsed operating states. In particular, for power devices under pulsed operating states, it can perform time-resolved temperature testing and has high spatial and time resolutions, which is beneficial to the thermal design and research on thermal problems of power devices.

[0136] The following is an apparatus embodiment of the present invention, which can be used to implement the method embodiment of the present invention. For details not disclosed in the apparatus embodiment, please refer to the method embodiment of the present invention.

[0137] A measurement system for the thermal distribution of a power device with time and space resolution provided in another embodiment of the present invention includes:

[0138] A calibration module for calibrating the temperature-Raman shift coefficient of the power device to be measured;

[0139] A first temperature distribution acquisition module for measuring and obtaining the time and space resolved temperature distribution of the power device based on the calibrated temperature-Raman shift coefficient under pulsed operating states;

[0140] Wherein, the step of measuring and obtaining the time and space resolved temperature distribution of the power device under pulsed operating states includes:

[0141] At room temperature, apply a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c to the drain, keep the pulsed laser synchronized with the electrical pulse signal, and under the condition that the gate voltage is less than the threshold voltage of the power device to be measured, use the pulsed laser to detect the power device to be measured to obtain the first Raman shift at room temperature for all measurement points in the preset target space;

[0142] At room temperature, apply a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c to the drain, keep the pulsed laser synchronized with the electrical pulse signal, and the delay between the pulsed laser and the electrical pulse signal is t d p d d p d p p d d d

[0143] d dThe transient temperature at that time, adjust the delay time based on the preset delay time to increase the step size, and obtain the time and space-resolved temperature distribution of the power device.

[0144] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0145] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the flows and / or blocks in the flowchart and / or block diagram can also be implemented. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the functions specified in Figure 1 one or more of these flows Figure 1 or multiple flows and / or blocks

[0146] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the functions specified in Figure 1 one or more of these flows Figure 1 or multiple flows and / or blocks

[0147] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Therefore, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one or more of these flows Figure 1 or multiple flows and / or blocks

[0148] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific implementation manners of the present invention, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for measuring the thermal distribution of a power device with time and space resolution, characterized in that It includes the following steps: Calibrate the temperature-Raman shift coefficient of the power device to be measured; Based on the calibrated temperature-Raman shift coefficient, measure the time- and space-resolved temperature distribution of the power device in the pulsed operating state; Among them, the step of measuring the time- and space-resolved temperature distribution of the power device in the pulsed operating state includes: At room temperature, a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain. While keeping the pulsed laser synchronized with the electrical pulse signal, the power device to be measured is detected using the pulsed laser under the condition that the gate voltage is less than the threshold voltage of the power device to be measured, and the first Raman shift at room temperature of all measurement points in the preset target space is obtained. At room temperature, a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain. The pulsed laser is kept synchronized with the electrical pulse signal, and the delay between the pulsed laser and the electrical pulse signal is t d . When the gate voltage is greater than or equal to the threshold voltage of the power device to be measured, the power device to be measured is detected using a pulsed laser with a pulse width of t p , and the Raman shift in the pulsed operating state of all measurement points in the preset target space at the delay time t d is obtained. For each measurement point in the preset target space, the transient temperature of the measurement point at the delay time t is calculated based on the Raman shift at the first room temperature, the Raman shift in the pulsed working state, and the temperature-Raman shift coefficient. The delay time is adjusted based on the preset delay time increment step to obtain the time- and space-resolved temperature distribution of the power device. d When the delay time is adjusted, the time- and space-resolved temperature distribution of the power device can be obtained.

2. The measuring method of the thermal distribution of a power device with time and space resolution according to claim 1, characterized in that During the process of calibrating the temperature-Raman shift coefficient of the power device to be measured, The temperature interval is greater than or equal to 5°C; The temperature calibration range is from room temperature to 300°C.

3. The measurement method of the thermal distribution of a power device with time and space resolution according to claim 1, characterized in that, The laser power of the pulsed laser is less than or equal to 1 W; The pulse width t of the electrical pulse signal e is greater than the pulse width t of the pulsed detection laser p .

4. A method for measuring the thermal distribution of a power device with time and space resolution according to claim 1, characterized in that The step of measuring the time- and space-resolved temperature distribution of the power device in the pulsed operating state specifically includes: For any measurement point (x m , y n ) within the preset target space, when the gate voltage is less than the threshold voltage of the power device to be measured, a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain. Keep the pulsed laser synchronized with the electrical pulse signal, and use the pulsed laser to detect the power device to be measured, so as to obtain the Raman shift w mn of the measurement point (x m , y n ) at room temperature T r ; For the measurement point (x m , y n ), when the gate voltage is greater than or equal to the threshold voltage of the power device to be measured, a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain. Keep the pulsed laser synchronized with the electrical pulse signal, and the delay between the pulsed laser and the electrical pulse signal is t d . Use the pulsed laser to detect the power device to be measured, and obtain the Raman shift w d1 at the pulsed working state and the delay time t mn (t d1 ); Based on the Raman shift w mn , the pulsed operating state, and the delay time t d1 The Raman shift w mn (t d1 ), and the temperature-Raman shift coefficient k, calculate the transient temperature T(x m , y n ) at the measurement point at the delay time t d1 as T(x m , y n , t d1 ); For the measurement point (x m , y n ), increase the delay time in steps of t step by means of a signal generator, and repeat the steps of obtaining the transient temperature until the transient temperature T(x dn , y m , t n , t dn ) at the delay time t dn ) is obtained; Combining the transient temperatures at different delay times, the time-resolved transient temperature T(x m , y n ), within the working interval t d1 to t dn for the measurement point (x m , y n , t) is obtained; Among them, the transient temperature The delay time t d1 Is less than the pulse width t e And the pulse interval t c The sum; the transient temperature The delay time t dn Is less than the repetition frequency of the electrical pulse signal; the delay time t dn = t d1 +(n - 1)×t step , where n is any natural number; the increasing step size of the delay time is greater than or equal to the pulse width t of the pulsed detection laser p ; Transient temperature T(x m ,y n ,t) = {T(x m ,y n ,t d1 ), T(x m ,y n ,t d2 ), ……, T(x m ,y n ,t dn )}。 5. A method for measuring the thermal distribution of a power device with temporal and spatial resolution according to claim 1, characterized in that It also includes the following steps: Based on the calibrated temperature-Raman shift coefficient, measure the space-resolved temperature distribution of the power device in the DC operating state.

6. The measuring method of the thermal distribution of a power device with time and space resolution according to claim 5, characterized in that, The step of measuring the space-resolved temperature distribution of the power device in the DC operating state includes: At room temperature, when the gate voltage is less than the threshold voltage of the power device to be measured and a DC bias voltage is applied, use a continuous laser to detect the power device to be measured, and obtain the second Raman shift at room temperature of all measurement points in the preset target space; At room temperature, when a DC bias voltage is applied, use a continuous laser to detect the power device to be measured, and obtain the Raman shift in the DC operating state of all measurement points in the preset target space; For each measurement point in the preset target space, calculate the steady-state temperature based on the second Raman shift at room temperature, the Raman shift in the DC operating state, and the temperature-Raman shift coefficient, and obtain the space-resolved temperature distribution of the power device.

7. A measurement system for the thermal distribution of a power device with time and space resolution, characterized in that, It includes: A calibration module for calibrating the temperature-Raman shift coefficient of the power device to be measured; A first temperature distribution acquisition module for measuring the time- and space-resolved temperature distribution of the power device in the pulsed operating state based on the calibrated temperature-Raman shift coefficient; Among them, the step of measuring the time- and space-resolved temperature distribution of the power device in the pulsed operating state includes: At room temperature, a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain. While keeping the pulsed laser synchronized with the electrical pulse signal, the power device to be measured is detected using the pulsed laser under the condition that the gate voltage is less than the threshold voltage of the power device to be measured, and the first Raman shift at room temperature of all measurement points in the preset target space is obtained. At room temperature, a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain. The pulsed laser is kept synchronized with the electrical pulse signal, and the delay between the pulsed laser and the electrical pulse signal is t d . When the gate voltage is greater than or equal to the threshold voltage of the power device to be measured, the power device to be measured is detected using a pulsed laser with a pulse width of t p , and the Raman shift under the pulsed working state of all measurement points in the preset target space at the delay time t d is obtained. For each measurement point in the preset target space, calculate the transient temperature of the measurement point at the delay time t based on the Raman shift at the first room temperature, the Raman shift in the pulsed working state, and the temperature-Raman shift coefficient. Adjust the delay time based on the preset step size of the delay time increase to obtain the time- and space-resolved temperature distribution of the power device. d When the delay time is adjusted, the time- and space-resolved temperature distribution of the power device can be obtained.

8. A measurement system for the thermal distribution of a power device with temporal and spatial resolution according to claim 7, characterized in that, The step of measuring the time- and space-resolved temperature distribution of the power device in the pulsed operating state specifically includes: For any measurement point (x m , y n ) within a preset target space, when the gate voltage is less than the threshold voltage of the power device to be measured, a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain. Keep the pulsed laser synchronized with the electrical pulse signal, and use the pulsed laser to detect the power device under measurement, so as to obtain the Raman shift w m , y n ) of the measurement point (x r ) at room temperature T mn ; For the measurement point (x m , y n ), when the gate voltage is greater than or equal to the threshold voltage of the power device to be measured, a high-frequency electrical pulse signal with a pulse width of t e and an interval of t c is applied to the drain. Keep the pulsed laser synchronized with the electrical pulse signal, and the delay between the pulsed laser and the electrical pulse signal is t d . Use the pulsed laser to detect the power device to be measured, and obtain the Raman shift w d1 at the pulsed working state and the delay time t mn (t d1 ); Based on the Raman shift w mn , the pulsed working state, and the delay time t d1 The Raman shift w mn (t d1 ), and the temperature-Raman shift coefficient k, calculate the transient temperature T(x m , y n ) at the measurement point at the delay time t d1 , namely, T(x m , y n , t d1 ); For the measurement point (x m , y n ), the signal generator is used to increase the delay time in steps of t step , and the steps of obtaining the transient temperature are repeated until the transient temperature T(x dn , y m , t n , t dn ) at the delay time t dn is obtained; Combining the transient temperatures at different delay times, the time-resolved transient temperature T(x m , y n ), at the measurement point within the working interval from t d1 to t dn is obtained; m , y n , t); Among them, the transient temperature delay time t d1 is less than the pulse width t e and the pulse interval t c sum; the transient temperature delay time t dn is less than the repetition frequency of the electrical pulse signal; the delay time t dn = t d1 +(n - 1)×t step , where n is any natural number; the increasing step size of the delay time is greater than or equal to the pulse width t of the pulsed detection laser p ; Transient temperature T(x , , y m , t) = {T(x m , y n , t d1 ), T(x m , y n , t d2 ), ……, T(x m , y n , t dn )}.

9. The measuring system for the thermal distribution of a power device with time and space resolution according to claim 7, characterized in that, It also includes: A second temperature distribution acquisition module for measuring the space-resolved temperature distribution of the power device in the DC operating state based on the calibrated temperature-Raman shift coefficient.

10. The measurement system for the thermal distribution of a power device with time and space resolution according to claim 9, wherein, The step of measuring the space-resolved temperature distribution of the power device in the DC operating state includes: At room temperature, when the gate voltage is less than the threshold voltage of the power device to be measured and a DC bias voltage is applied, use a continuous laser to detect the power device to be measured, and obtain the second Raman shift at room temperature of all measurement points in the preset target space; At room temperature, when a DC bias voltage is applied, use a continuous laser to detect the power device to be measured, and obtain the Raman shift in the DC operating state of all measurement points in the preset target space; For each measurement point in the preset target space, calculate the steady-state temperature based on the second Raman shift at room temperature, the Raman shift in the DC operating state, and the temperature-Raman shift coefficient, and obtain the space-resolved temperature distribution of the power device.

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