Temperature detection method and test structure
By using a SiC semiconductor layer for heat treatment in the cavity to be measured, the surface parameters after Si atoms are precipitated are detected, which solves the problem of inaccurate high-temperature temperature detection in the prior art and realizes accurate detection of high-temperature temperature.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI YOFC ADVANCED SEMICONDUCTOR CO LTD
- Filing Date
- 2026-01-09
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies cannot accurately detect high temperatures, especially those ≥1200℃, and the accuracy of existing methods is low.
A SiC semiconductor layer is used to perform heat treatment in the cavity to be measured, so that Si atoms are precipitated to the surface. The cavity temperature is determined by detecting surface parameters such as roughness and Si concentration.
It enables accurate detection of high temperatures, especially in the range of 1200℃ to 2000℃, thus improving the accuracy of the detection.
Smart Images
Figure CN122016067A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of semiconductor technology, and in particular relates to a temperature detection method and test structure. Background Technology
[0002] Related technologies use silicon wafer implantation activation rate to test resistivity to detect cavity temperature, but this is suitable for detecting low to medium temperatures and cannot detect high temperatures (e.g., ≥1200℃). Other technologies employ periodic temperature measurements and thermocouple calibration to detect high temperatures, but these methods have relatively low accuracy. Summary of the Invention
[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a temperature detection method and test structure capable of accurately detecting high-temperature temperatures.
[0004] In a first aspect, this application provides a temperature detection method, including: A test structure is provided, the test structure including a SiC semiconductor layer; The test structure is placed in the temperature chamber to be measured and subjected to heat treatment, so that Si atoms in the SiC semiconductor layer are precipitated to the first surface of the SiC semiconductor layer; Detect the surface parameters of the first surface; The actual temperature of the cavity to be measured is determined based on the surface parameters of the first surface.
[0005] According to the temperature detection method of this application, by heat-treating the SiC semiconductor layer in the cavity to be measured, the mobility of Si atoms in the SiC lattice increases at high temperature. They migrate to the surface of the SiC semiconductor layer through surface diffusion or vacancy mechanism. Surface dangling bonds or defects promote the precipitation of Si atoms. After the Si atoms are precipitated, they will affect the surface parameters of the surface. The surface parameters are different for different cavity temperatures. By detecting the surface parameters of the first surface, the actual temperature of the cavity to be measured can be determined, thereby achieving accurate detection of high temperature.
[0006] According to one embodiment of this application, the test structure further includes a substrate; The provided test structure includes: The SiC semiconductor layer is formed on one side of the substrate, and the first surface is the surface of the SiC semiconductor layer facing away from the substrate.
[0007] According to one embodiment of this application, the substrate includes at least one of a SiC substrate and a diamond substrate.
[0008] According to one embodiment of this application, the test structure further includes a carbon film; The provided test structure includes: The carbon film is formed on the first surface of the SiC semiconductor layer; the carbon film is removed during the heat treatment process.
[0009] According to one embodiment of this application, the thickness of the carbon film is positively correlated with the temperature of the heat treatment.
[0010] According to one embodiment of this application, determining the actual temperature of the cavity to be measured based on the surface parameters of the first surface includes: Based on the preset correspondence between surface parameters and cavity temperature, the cavity temperature corresponding to the surface parameters of the first surface is determined as the actual temperature of the cavity to be measured.
[0011] According to one embodiment of this application, the temperature of the heat treatment is set to a target temperature; The method further includes: Determine whether the actual temperature of the cavity to be measured deviates from the target temperature.
[0012] According to one embodiment of this application, the temperature of the heat treatment is greater than or equal to 1200°C and less than or equal to 2000°C.
[0013] According to one embodiment of this application, the surface parameters include at least one of roughness and Si concentration.
[0014] Secondly, this application provides a test structure, including: The SiC semiconductor layer includes a first surface and a second surface disposed opposite to each other; the SiC semiconductor layer is used to perform heat treatment in the cavity to be measured, so that Si atoms in the SiC semiconductor layer are precipitated to the first surface, and the actual temperature of the cavity to be measured is determined by detecting the surface parameters of the first surface.
[0015] According to one embodiment of this application, the test structure further includes: The substrate is located on the second surface of the SiC semiconductor layer.
[0016] According to one embodiment of this application, the substrate includes at least one of a SiC substrate and a diamond substrate.
[0017] According to one embodiment of this application, the test structure further includes: A carbon film is located on the first surface of the SiC semiconductor layer; the carbon film is used to be removed during the heat treatment process.
[0018] According to one embodiment of this application, the thickness of the carbon film is positively correlated with the temperature of the heat treatment.
[0019] The above-described one or more technical solutions in the embodiments of this application have at least one of the following technical effects: By heat-treating the SiC semiconductor layer in the temperature measurement cavity, the mobility of Si atoms in the SiC lattice increases at high temperatures. They migrate to the surface of the SiC semiconductor layer through surface diffusion or vacancy mechanisms. Surface dangling bonds or defects promote the precipitation of Si atoms. After Si atoms are precipitated, they affect the surface parameters of the surface. The surface parameters are different depending on the cavity temperature. By detecting the surface parameters of the first surface, the actual temperature of the temperature measurement cavity can be determined, thus achieving accurate detection of high-temperature temperatures.
[0020] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description
[0021] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic flowchart of the temperature detection method provided in the embodiments of this application; Figure 2 This is one of the structural schematic diagrams of the test structure provided in the embodiments of this application; Figure 3 This is one of the structural schematic diagrams of the temperature detection method provided in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of the semiconductor device provided in the embodiments of this application; Figure 5 This is a second schematic diagram of the test structure provided in the embodiments of this application; Figure 6 This is the third schematic diagram of the test structure provided in the embodiments of this application; Figure 7 This is the second structural schematic diagram of the temperature detection method provided in the embodiments of this application. Detailed Implementation
[0022] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.
[0023] The temperature detection method and test structure provided in the embodiments of this application are described below with reference to the accompanying drawings.
[0024] Figure 1This is a schematic flowchart of the temperature detection method provided in the embodiments of this application.
[0025] like Figure 1 As shown, the temperature detection method provided in this application embodiment includes steps 110 to 140.
[0026] Step 110: Provide a test structure, which includes a SiC semiconductor layer.
[0027] Combination Figure 2 As shown, the test structure 10 may include a single SiC semiconductor layer 2, or it may include a stacked structure formed by multiple SiC semiconductor layers 2. The SiC semiconductor layer 2 refers to a semiconductor layer made of SiC material.
[0028] The SiC semiconductor layer 2 can be doped with ions. The SiC semiconductor layer 2 can be doped with N-type dopant ions to form an N-type SiC semiconductor layer. N-type dopant ions can include P (phosphorus) or N (nitrogen) ions, etc. The SiC semiconductor layer 2 can also be doped with P-type dopant ions to form a P-type SiC semiconductor layer. P-type dopant ions can include Al (aluminum) ions or B (boron) ions, etc.
[0029] The SiC semiconductor layer 2 includes a first surface S1 and a second surface S2 disposed opposite to each other. Figure 2 The second surface S2 shown is the bottom surface of the SiC semiconductor layer 2, and the first surface S1 is the top surface of the SiC semiconductor layer 2.
[0030] It should be noted that the SiC semiconductor layer 2 can have the same structure as the SiC epitaxial layer in a semiconductor device (such as a SiC power device), such as the same thickness and the same doping concentration.
[0031] Step 120: Place the test structure in the temperature chamber to be measured and perform heat treatment to precipitate Si atoms from the SiC semiconductor layer to the first surface of the SiC semiconductor layer.
[0032] The temperature-measuring cavity is a cavity in a device capable of heat treatment. For example, the device can be a furnace tube, and the temperature-measuring cavity can be the cavity of the furnace tube. The temperature-measuring cavity can be used to fabricate semiconductor devices (such as SiC power devices), or it can be used to fabricate other structures or devices; no specific limitations are made here.
[0033] It should be noted that the SiC semiconductor layer 2 can be the same as the SiC epitaxial layer in the semiconductor device (such as a SiC power device) to be fabricated in the temperature measurement cavity.
[0034] As an example, the semiconductor device to be fabricated for the temperature measurement cavity is a Schottky barrier diode (SBD), such as... Figure 4As shown, the Schottky barrier diode includes a SiC substrate 11, a SiC epitaxial layer 12, an anode 13, and a cathode 14. The SiC epitaxial layer 12 is located on one side of the SiC substrate 11, the anode 13 is located on the side of the SiC epitaxial layer 12 away from the SiC substrate 11, and the cathode 14 is located on the side of the SiC substrate 11 away from the SiC epitaxial layer 12. The SiC semiconductor layer 2 in the test structure 10 can be connected to... Figure 4 The structure of the SiC epitaxial layer 12 in the Schottky barrier diode shown is the same, and they can be formed in the same process.
[0035] During the actual fabrication process of the temperature-testing cavity, the heat treatment temperature is set as the target temperature; that is, a heating device is used to heat the cavity to the target temperature. However, due to issues such as the accuracy of the heating device, environmental interference, and process parameter settings, the actual temperature of the cavity may deviate from the target temperature. This deviation will affect the performance and reliability of the fabricated structure, thus impacting the yield. Therefore, it is necessary to detect and monitor the actual temperature of the cavity.
[0036] In this embodiment, the test structure 10 is placed in the temperature-testing cavity, and the test structure 10 is heat-treated. It should be noted that the test structure 10 can be placed simultaneously with the structure to be prepared in the temperature-testing cavity, and the test structure 10 is heat-treated simultaneously during the actual preparation of the temperature-testing cavity. Alternatively, the test structure 10 can be placed separately in the temperature-testing cavity, and the test structure 10 is heat-treated before the actual preparation of the temperature-testing cavity.
[0037] The heat treatment temperature is set as the target temperature, which is the high-temperature temperature used in the actual fabrication process of the temperature-measuring cavity. At high temperature, the mobility of Si atoms in the SiC lattice of the SiC semiconductor layer 2 increases, and they migrate to the surface through surface diffusion or vacancy mechanisms. Surface dangling bonds or defects promote the precipitation of Si atoms. Si atoms precipitate to the first surface S1, forming a rough structure on the first surface S1, which combines with... Figure 3 As shown, the higher the temperature, the greater the precipitation rate of Si atoms in the SiC semiconductor layer 2, and the greater the surface parameters of the first surface S1 (such as the roughness of the formed rough structure and / or Si concentration). Therefore, the actual temperature of the cavity to be measured can be determined by detecting the surface parameters of the first surface S1 of the SiC semiconductor layer 2.
[0038] In some embodiments, the heat treatment temperature is greater than or equal to 1200°C and less than or equal to 2000°C.
[0039] At very low temperatures (below 1200℃), the Si atoms in the SiC semiconductor layer 2 have low mobility and cannot effectively precipitate to the first surface S1, thus making it impossible to detect the actual temperature of the temperature-measuring cavity using the surface parameters of the first surface S1 of the SiC semiconductor layer 2. At very high temperatures (above 2000℃), SiC undergoes crystal transformation and thermal decomposition reactions, again making it impossible to detect the actual temperature of the temperature-measuring cavity using the surface parameters of the first surface S1 of the SiC semiconductor layer 2. Between 1200℃ and 2000℃, the Si atoms in the SiC semiconductor layer 2 have increased mobility, migrating to the surface through surface diffusion or vacancy mechanisms. Surface dangling bonds or defects promote Si precipitation, affecting the surface parameters of the first surface S1 of the SiC semiconductor layer 2. Furthermore, the higher the temperature, the greater the Si atom precipitation rate, and the larger the surface parameters of the first surface S1.
[0040] Therefore, when the heat treatment temperature is 1200℃~2000℃, by setting the SiC semiconductor layer 2 in the test structure 1, the actual temperature of the cavity to be measured can be accurately detected.
[0041] Step 130: Detect the surface parameters of the first surface.
[0042] At different temperatures, the precipitation rate of Si atoms varies, resulting in different morphologies of the rough structure formed on the first surface S1 of the SiC semiconductor layer 2. Therefore, the surface parameters of the first surface S1 can include the morphological parameters of the rough structure formed on the first surface S1, such as roughness. Furthermore, at different temperatures, the precipitation rate of Si atoms varies, resulting in different Si concentrations on the first surface S1 of the SiC semiconductor layer 2. Therefore, the surface parameters of the first surface S1 can also include the Si concentration of the first surface S1.
[0043] In some embodiments, the surface parameters include at least one of roughness and Si concentration.
[0044] When surface parameters include roughness, the roughness of the first surface S1 can be detected using AFM (Atomic Force Microscopy). AFM scans the first surface S1 point by point, recording the Z-axis height data at each location to generate a three-dimensional surface topography image. By statistically analyzing parameters such as the standard deviation, root mean square (Rq), and average roughness (Ra) of these height data, the surface roughness can be quantified. AFM has ultra-high resolution, allowing for direct observation of the morphological features of the first surface and accurate detection of its roughness.
[0045] When surface parameters include Si concentration, the Si concentration of the first surface S1 can be detected by SIMS (secondary ion mass spectrometry). SIMS uses a high-energy primary ion beam (such as O) to detect the Si concentration of the first surface S1. - Cs +The sample surface is bombarded, causing surface atoms or molecules to sputter and ionize, forming secondary ions. These secondary ions are collected by a mass spectrometer and separated and detected based on their mass-to-charge ratio (m / z), thereby obtaining the Si element concentration. SIMS has ultra-high sensitivity and can detect extremely low concentrations of Si, thus accurately detecting the Si concentration on the first surface.
[0046] It should be noted that the roughness / Si concentration of the first surface S1 can also be detected using other equipment, and no specific limitation is made here.
[0047] Step 140: Determine the actual temperature of the cavity to be measured based on the surface parameters of the first surface.
[0048] The precipitation rate of Si atoms varies at different temperatures, resulting in different surface parameters on the first surface S1 of the SiC semiconductor layer 2. By detecting the surface parameters of the first surface, the actual temperature of the cavity under test can be determined, thus achieving accurate detection of high-temperature temperatures.
[0049] In some embodiments, step 140, determining the actual temperature of the cavity to be measured based on the surface parameters of the first surface, includes: Based on the preset correspondence between surface parameters and cavity temperature, the cavity temperature corresponding to the surface parameters of the first surface is determined as the actual temperature of the cavity to be measured.
[0050] When surface parameters include roughness, a pre-established correspondence between roughness and cavity temperature is created, such as establishing a roughness-cavity temperature relationship curve. Specifically, ideally, it is assumed that the set temperature of the cavity does not deviate from the actual temperature. Multiple identical test structures are provided, each including a SiC semiconductor layer. Multiple cavity temperatures are set sequentially. For each set cavity temperature, a test structure is placed in the cavity for heat treatment (i.e., the heat treatment temperature is the cavity temperature), causing Si atoms in the SiC semiconductor layer of the test structure to precipitate to the first surface of the SiC semiconductor layer. The roughness of the first surface is detected, and the set cavity temperature and the detected roughness are recorded and saved. After completing the tests at multiple cavity temperatures, a one-to-one correspondence between multiple cavity temperatures and multiple roughnesses is established and saved. The cavity temperature and roughness are positively correlated; that is, the higher the cavity temperature, the greater the roughness.
[0051] In actual testing, after detecting the roughness of the first surface S1 of the SiC semiconductor layer 2, the pre-established correspondence between roughness and cavity temperature is queried to determine the cavity temperature corresponding to the roughness of the first surface S1. This cavity temperature is the actual temperature of the cavity to be tested.
[0052] When surface parameters include Si concentration, a pre-established relationship between Si concentration and cavity temperature is created, such as establishing a Si concentration vs. cavity temperature curve. Specifically, ideally, it is assumed that the set cavity temperature does not deviate from the actual temperature. Multiple identical test structures are provided, each including a SiC semiconductor layer. Multiple cavity temperatures are sequentially set. For each set cavity temperature, a test structure is placed in the cavity for heat treatment (i.e., the heat treatment temperature is the cavity temperature), causing Si atoms in the SiC semiconductor layer of the test structure to precipitate to the first surface of the SiC semiconductor layer. The Si concentration on the first surface is detected, and the set cavity temperature and the detected Si concentration are recorded. After completing the tests at multiple cavity temperatures, a one-to-one correspondence between multiple cavity temperatures and multiple Si concentrations is established and recorded. The cavity temperature and Si concentration are positively correlated; that is, the higher the cavity temperature, the higher the Si concentration.
[0053] In actual testing, after detecting the Si concentration on the first surface S1 of the SiC semiconductor layer 2, the pre-established correspondence between Si concentration and cavity temperature is queried to determine the cavity temperature corresponding to the Si concentration on the first surface S1. This cavity temperature is the actual temperature of the cavity to be tested.
[0054] When surface parameters include roughness and Si concentration, the actual temperature of the cavity to be measured can be determined based on the roughness of the first surface S1, and the actual temperature of the cavity to be measured can be determined based on the Si concentration of the first surface S1. If the actual temperatures of the two cavities to be measured are different, the final actual temperature of the cavity to be measured can be determined by combining the actual temperatures of the two cavities, such as taking the average of the two actual temperatures as the final actual temperature of the cavity to be measured, in order to further improve the accuracy of temperature detection.
[0055] In some embodiments, the temperature of the heat treatment is set to a target temperature.
[0056] This temperature detection method also includes: Determine whether the actual temperature of the cavity to be measured deviates from the target temperature.
[0057] After determining the actual temperature of the cavity to be measured, the actual temperature of the cavity to be measured can be compared with the target temperature. If the actual temperature of the cavity to be measured is the same as the target temperature, it is determined that the actual temperature of the cavity to be measured has not deviated from the target temperature, and the cavity to be measured can be used to prepare the required structure. If the actual temperature of the cavity to be measured is different from the target temperature, it is determined that the actual temperature of the cavity to be measured deviates from the target temperature, and temperature calibration and repair operations can be performed on the cavity to be measured based on the temperature deviation.
[0058] In some embodiments, combined with Figure 5As shown, the test structure 10 also includes a substrate 1.
[0059] The test structure provided in step 110 includes: A SiC semiconductor layer 2 is formed on one side of substrate 1.
[0060] Combination Figure 5 As shown, a substrate 1 is first provided, and then at least one SiC semiconductor layer 2 is formed on one side of the substrate 1.
[0061] Substrate 1 can be doped with ions. Substrate 1 can be doped with N-type dopant ions to form an N-type substrate. Substrate 1 can also be doped with P-type dopant ions to form a P-type substrate. The doping type of substrate 1 and SiC semiconductor layer 2 can be the same.
[0062] The material of substrate 1 can be the same as the material of SiC semiconductor layer 2, or the material of substrate 1 can be different from the material of SiC semiconductor layer 2. Substrate 1 must be ensured not to react at high temperatures (e.g., ≥1200°C). In some embodiments, substrate 1 includes at least one of SiC substrate and diamond substrate.
[0063] It should be noted that substrate 1 can have the same structure as the substrate in a semiconductor device (such as a SiC power device), such as the same thickness and doping concentration. As an example, substrate 1 in test structure 10 can be... Figure 4 The SiC substrate 11 in the Schottky barrier diode shown has the same structure and can be formed in the same process.
[0064] The SiC semiconductor layer 2 includes a first surface S1 and a second surface S2 disposed opposite to each other. In the case where the test structure 10 includes a substrate 1 and a SiC semiconductor layer 2, the first surface S1 is the surface of the SiC semiconductor layer 2 facing away from the substrate 1, and the second surface S2 is the surface of the SiC semiconductor layer 2 close to the substrate 1.
[0065] In some embodiments, after forming a SiC semiconductor layer 2 on one side of the substrate 1, the test structure 10 undergoes a surface precleaning process. The surface precleaning is used to remove surface contaminants from the test structure 10 to improve the quality and adhesion of subsequent processes.
[0066] In some embodiments, combined with Figure 6 As shown, the test structure 10 also includes a carbon film 3.
[0067] The test structure provided in step 110 includes: A carbon film 3 is formed on the first surface S1 of the SiC semiconductor layer 2; the carbon film 3 is removed during the heat treatment process.
[0068] Combination Figure 6As shown, a carbon film 3 is formed on the first surface S1 of the SiC semiconductor layer 2 using chemical vapor deposition or sputtering methods.
[0069] It should be noted that at high temperatures, Si atoms in the SiC semiconductor layer 2 will precipitate onto the first surface S1, forming a rough structure on the first surface S1. The higher the temperature, the greater the precipitation rate of Si atoms in the SiC semiconductor layer 2, and the greater the roughness of the rough structure formed on the first surface S1. The actual temperature in the temperature-measuring cavity can be detected by the roughness of the first surface S1. However, when the temperature is too high, the roughness of the first surface S1 is too large, and the difference in roughness at different temperatures is not significant, making it impossible to effectively detect the actual temperature in the temperature-measuring cavity by means of roughness.
[0070] In this embodiment, a carbon film 3 is formed on the first surface S1 of the SiC semiconductor layer 2 to protect the first surface S1 of the SiC semiconductor layer 2. Figure 7 As shown, during the heat treatment process, the carbon film 3 is removed first, and then a rough structure is formed on the first surface S1 of the SiC semiconductor layer 2. This reduces the roughness of the rough structure formed on the first surface S1, improves the accuracy of temperature detection, and increases the detectable temperature range.
[0071] In some embodiments, the thickness of the carbon film 3 is positively correlated with the heat treatment temperature, that is, the higher the heat treatment temperature, the greater the thickness of the carbon film 3.
[0072] The higher the heat treatment temperature, the greater the precipitation rate of Si atoms in the SiC semiconductor layer 2, the greater the roughness of the first surface S1, and the smaller the roughness difference. Conversely, the greater the thickness of the carbon film 3, the more it can reduce the roughness of the first surface S1 and effectively increase the roughness difference.
[0073] In this embodiment, the thickness of the carbon film 3 is positively correlated with the temperature of the heat treatment, ensuring that the roughness of the rough structure formed on the first surface S1 of the SiC semiconductor layer 2 at different temperatures has significant differences, thereby improving the accuracy of temperature detection and increasing the detectable temperature range.
[0074] It should be noted that when the heat treatment temperature is relatively low, such as 1200℃~1400℃, the test structure 10 may not have a carbon film 3. That is, the test structure 10 may include the SiC semiconductor layer 2, or the test structure 10 may include the substrate 1 and the SiC semiconductor layer 2. The roughness varies greatly at different temperatures. The actual temperature of the cavity under test can be accurately detected by measuring the roughness of the first surface S1 of the SiC semiconductor layer 2.
[0075] When the heat treatment temperature is relatively high, such as 1400℃~2000℃, the test structure 10 can be equipped with a carbon film 3. That is, the test structure 10 can include a SiC semiconductor layer 2 and a carbon film 3, or the test structure 10 can include a substrate 1, a SiC semiconductor layer 2, and a carbon film 3. By removing the carbon film 3 during the heat treatment process, the roughness of the first surface S1 of the SiC semiconductor layer 2 is reduced, so as to more accurately detect the actual temperature of the temperature-measuring cavity based on the reduced roughness.
[0076] It should be noted that when the roughness of the first surface S1 is reduced by carbon film 3, the roughness of the first surface S1 of SiC semiconductor layer 2 formed at different temperatures is still different, and the roughness of the first surface S1 of SiC semiconductor layer 2 formed at relatively high temperatures is still greater than the roughness formed at relatively low temperatures.
[0077] According to the temperature detection method provided in the embodiments of this application, by heat-treating the SiC semiconductor layer in the cavity to be measured, the mobility of Si atoms in the SiC lattice increases at high temperature. They migrate to the surface of the SiC semiconductor layer through surface diffusion or vacancy mechanisms. Surface dangling bonds or defects promote the precipitation of Si atoms. After the Si atoms are precipitated, they affect the surface parameters of the surface. The surface parameters are different depending on the cavity temperature. By detecting the surface parameters of the first surface, the actual temperature of the cavity to be measured is determined, thereby achieving accurate detection of high temperature.
[0078] Accordingly, this application also provides a test structure that can be applied to the temperature detection method in the above embodiments.
[0079] like Figure 2 As shown, the test structure 10 provided in this embodiment includes a SiC semiconductor layer 2, including a first surface S1 and a second surface S2 disposed opposite to each other. The SiC semiconductor layer 2 is used to perform heat treatment in the temperature-testing cavity, causing Si atoms in the SiC semiconductor layer 2 to precipitate onto the first surface S1. The actual temperature of the temperature-testing cavity is determined by detecting the surface parameters of the first surface S1.
[0080] SiC semiconductor layer 2 can be doped with ions. SiC semiconductor layer 2 can be doped with N-type dopant ions to form an N-type SiC semiconductor layer, or SiC semiconductor layer 2 can be doped with P-type dopant ions to form a P-type SiC semiconductor layer.
[0081] It should be noted that the SiC semiconductor layer 2 can have the same structure as the SiC epitaxial layer in a semiconductor device (such as a SiC power device), such as the same thickness and the same doping concentration.
[0082] During temperature detection, the test structure 10 is placed in the temperature-measuring cavity and subjected to heat treatment. The heat treatment temperature is set as the target temperature, which is the high-temperature temperature used in the actual fabrication process of the temperature-measuring cavity. At high temperature, the mobility of Si atoms in the SiC lattice of the SiC semiconductor layer 2 increases, and they migrate to the surface through surface diffusion or vacancy mechanisms. Surface dangling bonds or defects promote the precipitation of Si atoms. Si atoms precipitate to the first surface S1, forming a rough structure on the first surface S1, which combines with... Figure 3 As shown. The higher the temperature, the greater the precipitation rate of Si atoms in the SiC semiconductor layer 2, the greater the roughness of the rough structure formed by the first surface S1, and the greater the Si concentration of the first surface S1. By detecting the surface parameters of the first surface S1, which may include at least one of roughness and Si concentration, the actual temperature of the cavity to be measured can be determined.
[0083] The test structure 10 in this embodiment can accurately detect the actual temperature (e.g., 1200℃~2000℃) of the cavity to be tested.
[0084] In some embodiments, such as Figure 5 As shown, test structure 10 also includes: Substrate 1, located on the second surface S2 of SiC semiconductor layer 2. First surface S1 is the surface of SiC semiconductor layer 2 facing away from substrate 1.
[0085] Substrate 1 can be doped with ions. Substrate 1 can be doped with N-type dopant ions to form an N-type substrate. Substrate 1 can also be doped with P-type dopant ions to form a P-type substrate. The doping type of substrate 1 and SiC semiconductor layer 2 can be the same.
[0086] It should be noted that substrate 1 can have the same structure (e.g., same thickness) and doping concentration as the substrate in a semiconductor device (such as a SiC power device).
[0087] The material of substrate 1 can be the same as the material of SiC semiconductor layer 2, or the material of substrate 1 can be different from the material of SiC semiconductor layer 2. Substrate 1 must be ensured not to react at high temperatures (e.g., ≥1200°C). In some embodiments, the substrate includes at least one of SiC substrate and diamond substrate.
[0088] In some embodiments, such as Figure 6 As shown, the test structure also includes: Carbon film 3 is located on the first surface S1 of SiC semiconductor layer 2; carbon film 3 is used to be removed during heat treatment.
[0089] It should be noted that at high temperatures, Si atoms in the SiC semiconductor layer 2 will precipitate onto the first surface S1, forming a rough structure on the first surface S1. The higher the temperature, the greater the precipitation rate of Si atoms in the SiC semiconductor layer 2, and the greater the roughness of the rough structure formed on the first surface S1. The actual temperature in the temperature-measuring cavity can be detected by the roughness of the first surface S1. However, when the temperature is too high, the roughness of the first surface S1 is too large, and the difference in roughness at different temperatures is not significant, making it impossible to effectively detect the actual temperature in the temperature-measuring cavity by means of roughness.
[0090] In this embodiment, a carbon film 3 is formed on the first surface S1 of the SiC semiconductor layer 2 to protect the first surface S1 of the SiC semiconductor layer 2, thereby reducing the roughness of the rough structure formed on the first surface S1, improving the accuracy of temperature detection, and increasing the detectable temperature range.
[0091] In some embodiments, the thickness of the carbon film 3 is positively correlated with the heat treatment temperature, that is, the higher the heat treatment temperature, the greater the thickness of the carbon film 3.
[0092] The higher the heat treatment temperature, the greater the precipitation rate of Si atoms in the SiC semiconductor layer 2, the greater the roughness of the first surface S1, and the smaller the roughness difference. Conversely, the greater the thickness of the carbon film 3, the more it can reduce the roughness of the first surface S1 and effectively increase the roughness difference.
[0093] In this embodiment, the thickness of the carbon film 3 is positively correlated with the temperature of the heat treatment, ensuring that the roughness of the rough structure formed on the first surface S1 of the SiC semiconductor layer 2 at different temperatures has significant differences, thereby improving the accuracy of temperature detection and increasing the detectable temperature range.
[0094] In summary, according to the test structure provided in the embodiments of this application, by heat-treating the SiC semiconductor layer in the cavity to be measured, the mobility of Si atoms in the SiC lattice increases at high temperatures. They migrate to the surface of the SiC semiconductor layer through surface diffusion or vacancy mechanisms. Surface dangling bonds or defects promote the precipitation of Si atoms. After the Si atoms are precipitated, they affect the surface parameters of the surface. Moreover, the surface parameters are different depending on the cavity temperature. By detecting the surface parameters of the first surface, the actual temperature of the cavity to be measured can be determined, thereby achieving accurate detection of high temperature.
[0095] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and are not limited in number; for example, a first object can be one or more.
[0096] In the description of this application, "multiple" means two or more.
[0097] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0098] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.
Claims
1. A temperature detection method, characterized in that, include: A test structure is provided, the test structure including a SiC semiconductor layer; The test structure is placed in the temperature chamber to be measured and subjected to heat treatment, so that Si atoms in the SiC semiconductor layer are precipitated to the first surface of the SiC semiconductor layer; Detect the surface parameters of the first surface; The actual temperature of the cavity to be measured is determined based on the surface parameters of the first surface.
2. The temperature detection method according to claim 1, characterized in that, The test structure also includes a substrate; The provided test structure includes: The SiC semiconductor layer is formed on one side of the substrate, and the first surface is the surface of the SiC semiconductor layer facing away from the substrate.
3. The temperature detection method according to claim 2, characterized in that, The substrate includes at least one of SiC substrate and diamond substrate.
4. The temperature detection method according to claim 1, characterized in that, The test structure also includes a carbon film; The provided test structure includes: The carbon film is formed on the first surface of the SiC semiconductor layer; the carbon film is removed during the heat treatment process.
5. The temperature detection method according to claim 4, characterized in that, The thickness of the carbon film is positively correlated with the temperature of the heat treatment.
6. The temperature detection method according to claim 1, characterized in that, Determining the actual temperature of the cavity to be measured based on the surface parameters of the first surface includes: Based on the preset correspondence between surface parameters and cavity temperature, the cavity temperature corresponding to the surface parameters of the first surface is determined as the actual temperature of the cavity to be measured.
7. The temperature detection method according to claim 1, characterized in that, The temperature of the heat treatment is set to the target temperature; The method further includes: Determine whether the actual temperature of the cavity to be measured deviates from the target temperature.
8. The temperature detection method according to claim 1, characterized in that, The heat treatment temperature is greater than or equal to 1200℃ and less than or equal to 2000℃.
9. The temperature detection method according to any one of claims 1-8, characterized in that, The surface parameters include at least one of roughness and Si concentration.
10. A test structure, characterized in that, include: The SiC semiconductor layer includes a first surface and a second surface disposed opposite to each other; the SiC semiconductor layer is used to perform heat treatment in the cavity to be measured, so that Si atoms in the SiC semiconductor layer are precipitated to the first surface, and the actual temperature of the cavity to be measured is determined by detecting the surface parameters of the first surface.
11. The test structure according to claim 10, characterized in that, The test structure also includes: The substrate is located on the second surface of the SiC semiconductor layer.
12. The test structure according to claim 11, characterized in that, The substrate includes at least one of SiC substrate and diamond substrate.
13. The test structure according to any one of claims 10-12, characterized in that, The test structure also includes: A carbon film is located on the first surface of the SiC semiconductor layer; the carbon film is used to be removed during the heat treatment process.
14. The test structure according to claim 13, characterized in that, The thickness of the carbon film is positively correlated with the temperature of the heat treatment.