Sample holder for epitaxial growth of double-layer growth substrates

Abstract

The present invention discloses a sample holder for epitaxial growth of a double-layer structure growth substrate, comprising a tray body and a mask plate, wherein the tray body is provided with a main containing groove for containing a growth substrate and a sub-containing groove for containing a reference substrate, the mask plate is slidably mounted on the tray body along a sliding track arranged along the centrifugal direction of the rotation of the tray body, the sub-containing groove is located at a first position and a second position arranged from back to front along the sliding track, the mask plate slides between a sliding rear position and a sliding front position along the sliding track to switch and cover the sub-containing groove at the first position and the sub-containing groove at the second position, and the contact surface between the mask plate and the sliding track is smooth, so that the mask plate can switch from covering the sub-containing groove at the first position to covering the sub-containing groove at the second position under the action of inertia when the tray body is decelerated. The present invention can switch and cover the reference substrate by the inertial sliding of the mask plate, and obtain a single-layer sample of each epitaxial layer growth during the production of a double-layer epitaxial layer.

Description

Technical Field

[0001] The invention relates to the technical field of crystal synthesis, and in particular to a sample holder used for growing a double-layer silicon carbide epitaxial wafer using a high-temperature chemical vapor deposition device. Background Art

[0002] Silicon carbide single crystal material has the advantages of high thermal conductivity, high breakdown field strength, high saturated electron drift rate and high bonding energy, which can well meet the application requirements of modern electronic technology in harsh conditions such as high temperature, high power, high voltage, high frequency and high radiation. Unlike traditional silicon material devices, silicon carbide devices cannot be directly made on silicon carbide single crystal materials. It is necessary to grow a high-quality epitaxial layer on a single crystal substrate, and then manufacture various types of devices on the epitaxial layer. According to the design requirements of the power device, a single or multi-layer epitaxial layer is required. Compared with the more mature single-layer epitaxial structure, the epitaxial growth of two or more multi-layer structures not only needs to overcome the difficulties of the growth process, but also has technical barriers in doping concentration and thickness detection.

[0003] During the chemical vapor deposition (CVD) growth process, silicon carbide and doping elements attached to the graphite accessories in the furnace cannot be completely removed by high temperature. They will be heated again and precipitated during the next furnace growth, which directly leads to the irregular increase of the doping concentration of each furnace of epitaxial materials under the same doping element gas flow rate. The industry calls it "doping concentration drift". When growing a single layer of epitaxial material, the experimenter generally corrects the flow rate of the doping element gas according to the doping concentration drift of the epitaxial wafer in the previous furnace. However, the conventional doping concentration detection means (mercury probe CV) and thickness detection means (Fourier transform infrared spectroscopy, FTIR) in mass production cannot measure and distinguish the doping concentration and thickness of each layer in the multi-layer structure epitaxial layer separately. Therefore, when performing multi-layer epitaxial growth, it is generally necessary to perform blind adjustments for several furnaces based on experience, and then grow the second layer of epitaxial separately for indirect detection and correction to prevent the doping concentration and thickness from exceeding the internal control standard. The industry calls it "companion wafer". Taking the simplest double-layer epitaxial structure as an example, generally, a follow-up wafer is required after a maximum of six wafers are grown. For high-specification products, the number of follow-up wafers is often shortened to three wafers, resulting in a huge waste of cost and production capacity.

[0004] Currently, the only method that can directly characterize the epitaxial doping concentration and thickness of each layer of a multilayer structure is secondary ion mass spectrometry (SIMS), but its disadvantages are that it is expensive and a destructive test. After the test, the silicon carbide epitaxial wafer cannot be used again, so the method cannot be promoted and applied in mass production for the time being. Especially when testing the double-layer epitaxial layer, it is even more difficult to replace the test with other methods.

[0005] Therefore, there is an urgent need for a sample holder that can solve the above problem and provide samples for testing epitaxial layer parameters during multi-layer epitaxial growth. Summary of the invention

[0006] The purpose of the present invention is to provide a sample holder for epitaxial growth of a double-layer structure growth substrate, which can cover a reference substrate by inertial sliding switching of a mask plate, and obtain a single-layer sample of each epitaxial layer growth when producing a double-layer epitaxial layer.

[0007] In order to achieve the above-mentioned purpose, the present invention discloses a sample holder for epitaxial growth of a double-layer structure growth substrate, comprising a tray body and a mask plate, wherein the tray body is provided with a main containing groove for containing the growth substrate and a sub-containing groove for containing the reference substrate, the mask plate is slidably mounted on the tray body along a sliding track, the sliding track is arranged along the centrifugal direction of rotation of the tray body and is provided with a limiting portion for limiting the mask plate from sliding from a front position of the sliding track to a rear position of the sliding track, the sub-containing groove is located at a first position and a second position arranged from back to front along the sliding track, the mask plate slides along the sliding track between the rear position and the front position to switch between covering the sub-containing groove at the first position and the sub-containing groove at the second position, and the contact surface between the mask plate and the sliding track is a smooth sliding surface, so that the mask plate can slide from back to front on the sliding track under the action of inertia when the tray body is decelerated, and switch from covering the sub-containing groove at the first position to covering the sub-containing groove at the second position.

[0008] Preferably, the sliding track is an arc-shaped sliding track with the rotation center of the tray body as its center.

[0009] Preferably, the limiting portion comprises a clamping groove which is arranged on the track surface of the sliding track at a position corresponding to the sliding front position and which is concave-convexly matched with the supporting foot of the mask plate.

[0010] Preferably, the sliding rail includes a first sliding rail corresponding to the first position of the auxiliary accommodating groove and a second sliding rail corresponding to the second position of the auxiliary accommodating groove, and the mask plate includes a covering body, a first supporting foot for supporting the covering body slidably on the track surface of the first sliding rail, and a second supporting foot for supporting the covering body slidably on the track surface of the second sliding rail, and the height of the track surface of the first sliding rail is lower than the track surface of the second sliding rail.

[0011] Specifically, the height difference between the first supporting foot and the second supporting foot is equal to the height difference between the track surface of the first slide rail and the track surface of the second slide rail.

[0012] Specifically, a first slot is formed at one end of the first slide rail close to the second slide rail to limit the first supporting foot of the mask plate that switches to slide to the front sliding position, and a second slot is formed at one end of the second slide rail away from the first slide rail to limit the second supporting foot of the mask plate that switches to slide to the front sliding position, and the limiting portion includes the first slot and the second slot.

[0013] Preferably, the tray body is provided with a main accommodating area and a secondary accommodating area, the main accommodating groove is opened on the main accommodating area, the secondary accommodating groove is opened on the secondary accommodating area, the main accommodating area is arranged in the middle of the tray body, the secondary accommodating area extends from the edge of the tray body and is arranged around the main accommodating area, and the area of ​​the main accommodating groove is larger than the area of ​​the secondary accommodating groove.

[0014] Among them, the cross-section of the main containing groove is a circle with straight edges, the diameter of the circle is 150mm, the cross-section of the auxiliary containing groove is a rectangle or a quasi-rectangular shape with a length and width of 15mm, the depth of the main containing groove and the auxiliary containing groove is 2mm, the distance between the main containing groove and the auxiliary containing groove is greater than or equal to 0.5mm and less than or equal to 1.5mm, the opening shape of the main containing groove is a circle with straight edges, and the opening shape of the main containing groove is a rhombus or a quasi-rectangle composed of two arcs concentric with the main containing groove and two parallel straight lines.

[0015] Specifically, the auxiliary accommodating groove includes a first auxiliary accommodating groove located at a first position and a second auxiliary accommodating groove located at a second position.

[0016] Preferably, the surface roughness Ra of the contact surface between the mask plate and the sliding track is less than 10 nm. Of course, the specific value of the surface roughness of the contact surface is set by the technicians according to actual needs and is not limited thereto.

[0017] Preferably, the mask plate can slide from the sliding rear position to the sliding front position under the action of inertia when the preset speed decreases to 0 within a preset time when the tray body rotates along a preset direction, thereby switching from covering the auxiliary accommodating groove at the first position to covering the auxiliary accommodating groove at the second position.

[0018] Preferably, the preset rotation speed is the rotation speed of the tray body when the epitaxial layer is grown on the growth substrate.

[0019] Compared with the prior art, the sample holder of the present invention is provided with a main containing groove for placing the growth substrate and a sub-containing groove for placing the reference substrate, so that the epitaxial layer can be grown on the reference substrate simultaneously with the epitaxial layer growing on the growth substrate. Thus, the parameters of the epitaxial layer on the growth substrate can be determined by detecting the parameters of the epitaxial layer on the reference substrate, without destroying the epitaxial layer structure on the growth substrate. The present invention is suitable for epitaxial layer detection of products in large-scale batch production. On the other hand, the present invention sets a mask plate covering a partial area on the auxiliary containing groove, and the mask plate can slide from the sliding rear position to the sliding front position under the action of inertia when the tray body is rapidly decelerated, and switches from covering the auxiliary containing groove at the first position to covering the auxiliary containing groove at the second position, so that after the first epitaxial layer is grown on the growth substrate and the first epitaxial layer is grown on the reference substrate at the second position, the rotation of the tray body is stopped and the mask plate can be switched to cover the first position, so that the second epitaxial layer is grown on the growth substrate and the second epitaxial layer is grown on the reference substrate at the first position, so that the reference substrate at the first position and the reference substrate at the second position respectively form a single-layer first epitaxial layer and a single-layer second epitaxial layer, so as to respectively detect the epitaxial layer parameters of different layers on the growth substrate, and the detection is convenient and accurate without destroying the epitaxial layer on the growth substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural diagram of a sample holder used for epitaxial growth of a double-layer structure growth substrate according to the present invention.

[0021] Figure 2a It is a structural diagram of the tray body of the present invention.

[0022] Figure 2b yes Figure 2a Enlarged view of part a.

[0023] Figure 3a and Figure 3b It is a structural diagram of the mask at different angles.

[0024] Figure 4a and Figure 4b It is a connection structure between the auxiliary accommodating groove and the mask plate when the mask plate slides to the second position.

[0025] Figure 5a and Figure 5b It is a connection structure between the auxiliary accommodating groove and the mask plate when the mask plate slides to the first position.

[0026] Figure 6 This is a connection structure between the auxiliary receiving groove and the mask plate in another embodiment of the present invention.

[0027] Reference numerals: sample holder 100, tray body 10, main accommodating area 11, auxiliary accommodating area 12, mask plate 13, cover body 131, first supporting foot 132, second supporting foot 133, main accommodating groove 21, auxiliary accommodating groove 22, first auxiliary accommodating groove 221, second auxiliary accommodating groove 222, sliding rail 31, first slide rail 311, second slide rail 312, first clamping groove 313, second clamping groove 314 DETAILED DESCRIPTION

[0028] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, the following is a detailed description in conjunction with the implementation methods and the accompanying drawings.

[0029] refer to Figure 1 to Figure 2b The present invention discloses a sample holder 100 for epitaxial growth of a double-layer structure growth substrate, comprising a tray body 10, a main accommodating area 11, a secondary accommodating area 12 and a mask plate 13 opened on the tray body 10, wherein the main accommodating area 11 is provided with a main accommodating groove 21 for accommodating a growth substrate, the secondary accommodating area 12 is provided with a secondary accommodating groove 22 for accommodating a reference substrate, and the mask plate 13 is slidably installed on the tray body 10 along a sliding track 31 and covers a portion of the secondary accommodating groove 22 of the secondary accommodating area 12. The auxiliary receiving groove 22 is located at a first position and a second position arranged from back to front along the sliding track 31. The sliding track 31 has a spacing with the rotation center of the tray body 10 and is arranged along the centrifugal direction of rotation of the tray body 10. The mask plate 13 slides along the sliding track 31 between the sliding rear position of the sliding track and the sliding front position of the sliding track, and can switch to cover the auxiliary receiving groove 22 at the first position and the auxiliary receiving groove 22 at the second position. The contact surface between the mask plate 13 and the sliding track 31 is a smooth sliding surface, so that the mask plate 13 can slide on the sliding track 31 under the action of inertia when the tray body 10 decelerates, and switch from covering the auxiliary receiving groove 22 at the first position to covering the auxiliary receiving groove 22 at the second position.

[0030] Among them, a limiting portion is provided on the sliding track 31 to limit the mask plate 13 from sliding from the front sliding position of the sliding track 31 to the rear sliding position of the sliding track 31, and the limiting portion mainly limits the mask plate 13 from sliding from the front sliding position of the sliding track 31 to the rear sliding position of the sliding track 31 under the action of the centrifugal force when the tray body 10 rotates. In this embodiment, the limiting portion includes a clamping groove (313, 314) provided on the track surface of the sliding track 31 at a place corresponding to the front sliding position and concave-convexly matched with the support feet (132, 133) of the mask plate 13. Of course, it is not limited to this, and the limiting portion can also be other structures, such as a clamping channel located on the sliding track 31 and extending from the back to the front and gradually becoming smaller and deeper to clamp the support feet (132, 133), such as a small spring sheet provided on the track surface.

[0031] The surface roughness Ra of the contact surface between the mask plate 13 and the sliding track 31 is less than 10nm, and when the tray body 10 rotates in a preset direction, the preset speed is reduced to 0 within a preset time, and a relatively large throwing force is generated on the mask plate 13, so that the mask plate 13 slides from the sliding rear position to the sliding front position under the action of inertia, so that the mask plate 13 switches from covering the auxiliary accommodating groove 22 in the first position to covering the auxiliary accommodating groove 22 in the second position. The preset speed is the rotation speed of the tray body when the epitaxial layer is grown on the growth substrate, and the preset time is the time designed by the technician according to the actual situation.

[0032] The first position and the second position are arranged from back to front along the track direction of the sliding track 31, and the first position and the second position can be arranged at a distance or just connected. The rotation direction of the tray body 10 during the growth of the epitaxial layer is set to the forward direction, and the first position is located behind the second position, so that the mask plate 13 can be swung from the first covering position to the second covering position when the tray body is rapidly decelerated.

[0033] The sliding track 31 is an arc-shaped sliding track 31 with the rotation center as the center. This solution makes it easier for the mask plate 13 to slide along the sliding track 31 under the action of inertia. Of course, only the end of the sliding track 31 away from the second position of the auxiliary accommodating groove 22 can be an arc-shaped with the rotation center as the center, and the other parts are arc-shaped or straight tracks connected thereto with smooth transition.

[0034] The slide track 31 is arranged along the centrifugal direction of rotation of the tray body 10, which means that the arc of the slide track 31 does not face the rotation axis of the tray body 10, so that the speed change when the tray body 10 rotates can drive the mask plate 13 to swing along the slide track 31. Specifically, the slide track 31 is arranged along the centrifugal direction of rotation of the tray body 10, including: the slide track 31 is arranged along a circle with the rotation center of the tray body 10 as the center, along a tangent of a circle with the rotation center of the tray body 10 as the center, or the slide track is a smooth line combined with a circle with the rotation center of the tray body and a tangent of a circle with the rotation center of the tray body as the center, or the slide track is a spiral track with the rotation center of the tray body as the center.

[0035] refer to Figure 1 to Figure 2b , the main accommodating area 11 is arranged in the middle of the tray body 10, and the secondary accommodating area 12 is arranged around the main accommodating area 11 and extends to the edge of the tray body 10, so that the secondary accommodating groove 22 is arranged near the edge of the tray body 10, increasing the throwing force of the mask plate 13 when the tray body 10 is rapidly decelerated, and the area of ​​the main accommodating groove 21 is larger than the area of ​​the secondary accommodating groove 22. The cross section of the main accommodating groove 21 is a circle with straight edges, and the diameter of the circle is 150mm. The secondary accommodating groove 22 has two rectangular or quasi-rectangular cross sections with a length and width of 15mm, and the depth of the main accommodating groove 21 and the secondary accommodating groove 22 is 2mm. Of course, the shape of the secondary accommodating groove 22 is not limited to this, and can also be circular, elliptical, fan-shaped, etc.

[0036] The distance between the main receiving groove 21 and the auxiliary receiving groove is greater than or equal to 0.5 mm and less than or equal to 1.5 mm, the opening shape of the main receiving groove 21 is a circle with straight edges, and the opening shape of the main receiving groove 21 is a rhombus or rectangle consisting of two arcs concentric with the main receiving groove 21 and two parallel straight lines. In this embodiment, the tray body 10 is a round block with a thickness of 8 mm and an outer diameter of 220 mm. The sliding track 31 is an arc segment with a diameter of 166 mm and a diameter of 206 mm, the track arc length is 36 mm, the track width is 1 mm, and the spacing between the two arc segments is 20 mm.

[0037] refer to Figure 2b , Figure 4b and Figure 5b The sliding track 31 includes a first sliding track 311 corresponding to the first position and a second sliding track 312 corresponding to the second position. Figures 3a to 5bThe mask plate 13 includes a covering body 131, a first supporting foot 132 for slidingly supporting the covering body 131 on the first slide rail 311, and a second supporting foot 133 for slidingly supporting the covering body 131 on the second slide rail 312. The height of the track surface of the first slide rail 311 is lower than the track surface of the second slide rail 312, so as to form a step-shaped blocking surface 3111 between the track surface of the first slide rail 311 and the track surface of the second slide rail 312, and cooperate with the end blocking wall of the second slide rail 312 to limit the covering body 131. In this embodiment, the area of ​​the covering body 131 is 15mm×15mm. The distance between the first supporting foot 132 and the second supporting foot 133 is 16mm.

[0038] refer to Figure 4b and Figure 5b , the height difference between the first supporting foot 132 and the second supporting foot 133 is equal to the height difference between the track surface of the first slide rail 311 and the track surface of the second slide rail 312. The height difference between the track surface of the first slide rail 311 and the track surface of the second slide rail 312 is 1 mm.

[0039] refer to Figure 4b and Figure 5b A first blocking wall is formed at one end of the first slide rail 311 away from the second slide rail 312 to prevent the first supporting foot 132 from derailing, and a second blocking wall is formed at one end of the second slide rail 312 away from the first slide rail 311 to prevent the second supporting foot 133 from derailing.

[0040] refer to Figure 2b , Figure 4b and Figure 5b The first slide rail 311 has a first slot 313 formed at one end close to the second slide rail 312 to limit the first support leg 132 of the mask plate 13 switched to the front sliding position, and the second slide rail 312 has a second slot 314 formed at one end away from the first slide rail 311 to limit the second support leg 133 of the mask plate 13 switched to the front sliding position. The first slot 313 and the second slot 314 are cubic grooves of 1mm×1mm×1mm, the first support leg 132 is a cuboid of 0.9mm×0.6mm×4mm (height), and the second support leg 133 is a cuboid of 0.9mm×0.6mm×5mm (height).

[0041] refer to Figure 2b , Figure 4a and Figure 5aThe auxiliary receiving groove 22 includes a first auxiliary receiving groove 221 provided at the first position and a second auxiliary receiving groove 222 provided at the second position, the first auxiliary receiving groove 221 and the second auxiliary receiving groove 222 are arranged around the rotation center spacing, and the mask plate 13 can switch to cover the first auxiliary receiving groove 221 and the second auxiliary receiving groove 222, and completely expose the second auxiliary receiving groove 222 when covering the first auxiliary receiving groove 221, and expose the first auxiliary receiving groove 221 when covering the two auxiliary receiving grooves 22. In this embodiment, the tray body 10 is between the first auxiliary receiving groove 221 and the second auxiliary receiving groove 222. The cross-section of the first auxiliary receiving groove 221 and the second auxiliary receiving groove 222 is a rectangle or a quasi-rectangle with a length and width of 15 mm, and the depth of the first auxiliary receiving groove 221 and the second auxiliary receiving groove 222 is 2 mm. Of course, the shapes of the first auxiliary receiving groove 221 and the second auxiliary receiving groove 222 are not limited thereto, and may also be circular, elliptical, fan-shaped, or the like.

[0042] Of course, reference Figure 6 In another embodiment, there may be one auxiliary containing groove 22a, the first position and the second position are respectively the front half and the rear half of the auxiliary containing groove 22a, a reference substrate is installed in the auxiliary containing groove 22a, the mask plate 13 can switch to cover the front half and the rear half of the auxiliary containing groove 22a, after the epitaxial growth is completed, the concentration and thickness of the epitaxial layer grown on the front half and the rear half of the reference substrate in the auxiliary containing groove 22a can be respectively detected to judge the concentration and thickness of the first epitaxial layer and the second epitaxial layer on the growth substrate, wherein the front half and the rear half of the auxiliary containing groove 22a are respectively detected. The half-part spacing is set or is just connected. If the front half and the rear half of the auxiliary groove 22a are spaced apart, the area between the front half and the rear half of the auxiliary groove 22a can be fully covered or uncovered when the mask plate 13 switches to cover the front half and the rear half of the auxiliary groove 22a. When uncovered, the epitaxial layer grown between the front half and the rear half of the reference substrate is a double-layer epitaxial layer. The parameters of the double-layer epitaxial layer can be detected to verify the two-layer detection data separately, the parameters between the two epitaxial layers, or the parameters of the overall structure formed by the double-layer epitaxial layer.

[0043] refer to Figures 4a to 5b , describing the processing of the present invention:

[0044] refer to Figure 4a and Figure 4b , place the growth substrate in the main receiving groove 21, place the two reference substrates 201 and 202 in the first auxiliary receiving groove 221 and the second auxiliary receiving groove 222 respectively, move the mask plate 13 to the rear sliding position to cover the reference substrate 201 in the first auxiliary receiving groove 221, and expose the reference substrate 202 in the second auxiliary receiving groove 222. At this time, the mask plate 13 is located on the first slide rail 311.

[0045] The sample holder 100 is installed in the epitaxial growth device by rotating around its rotation center, and the holder body 10 is controlled to move along the Figure 2b Rotate in the direction of the middle arrow, rotate to a speed of 600 rpm and maintain a constant speed, and start using chemical vapor deposition (CVD) to grow an epitaxial layer on the substrate on the tray body 10, thereby growing a first epitaxial layer on the growth substrate and growing a first reference epitaxial layer on the reference substrate 202.

[0046] refer to Figure 5a and Figure 5b , control the tray body 10 to decrease its rotation speed from 600rpm to 0 within 30s, so that the mask plate 13 slides along the sliding track 31 under the action of inertial centrifugal force, and slides from the first slide rail 311 to the second slide rail 312. The mask plate 13 is inertially swung to the upper part of the sliding front position to cover the reference substrate 202 in the second sub-containing groove 222, and the reference substrate 201 in the first sub-containing groove 221 is exposed.

[0047] Control the tray body 10 along Figure 2b Rotate in the direction of the middle arrow, rotate to a speed of 600 rpm and maintain a constant speed, and start growing an epitaxial layer again on the substrate on the tray body 10 using chemical vapor deposition (CVD), thereby growing a second epitaxial layer on the growth substrate, and growing a second reference epitaxial layer on the reference substrate 201.

[0048] While forming the first epitaxial layer and the second epitaxial layer on the growth substrate, a reference substrate 202 on which the first reference epitaxial layer is grown alone and a reference substrate 201 on which the second reference epitaxial layer is grown are obtained, and the relevant parameters of the two epitaxial layers on the growth substrate, including doping concentration and thickness, etc., are obtained by detecting the first reference epitaxial layer on the reference substrate 202 and the second reference epitaxial layer on the reference substrate 201. The detection data of the first reference epitaxial layer is used as the data of the first epitaxial layer of the growth substrate, and the detection data of the second reference epitaxial layer is used as the data of the second epitaxial layer of the growth substrate.

[0049] The reference substrate 201 and the reference substrate 202 are tested for mercury probe CV and FTIR respectively to obtain the doping concentration and thickness of the first epitaxial layer and the second epitaxial layer of the growth substrate.

[0050] In this embodiment, the growth substrate and the reference substrate 201, 202 are silicon carbide substrates, the tray body 10 is made of graphite, and the surface of the tray body 10 is covered with a tantalum carbide coating. The reference substrate 201 and the reference substrate 202 after the epitaxial layer is grown are called silicon carbide reference experimental pieces, and the growth substrate after the epitaxial layer is grown is called a double-layer silicon carbide epitaxial wafer. The reference substrate 201 and the growth substrate are made of the same material, only the area size is different, and the material of the reference substrate and the growth substrate is not limited to silicon carbide.

[0051] Among them, the technicians tested the reference substrate 201, the reference substrate 202 and the epitaxial layer on the growth substrate obtained in the above test to verify the accuracy of the test method of the present invention. Among them, the mercury probe CV and FTIR were tested on two silicon carbide reference experimental pieces respectively, and the doping concentration and thickness of the first reference epitaxial layer and the second reference epitaxial layer of the double-layer silicon carbide epitaxial wafer were obtained. Compare the data of the first reference epitaxial layer and the second reference epitaxial layer measured from the two silicon carbide reference experimental pieces respectively with the data directly measured on the double-layer silicon carbide epitaxial wafer by secondary ion mass spectrometry (SIMS). Among them, SIMS itself has a low test accuracy for doping concentration and thickness, and can only be used as an estimate. Referring to Table 1 below, the difference between the values ​​measured by the reference experimental piece in this experiment and the SIMS data is generally within 20%. It can be determined that the reference experimental piece used in this scheme can better reflect the doping concentration and thickness of the first epitaxial layer and the second epitaxial layer of the double-layer silicon carbide epitaxial wafer after epitaxial growth.

[0052]

[0053] Table 1

[0054] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A sample holder for epitaxial growth of a double-layer growth substrate, characterized in that: The invention comprises a tray body and a mask plate, wherein the tray body is provided with a main containing groove for accommodating a growth substrate and a secondary containing groove for accommodating a reference substrate, the mask plate is slidably installed on the tray body along a sliding track, the sliding track is arranged along the centrifugal direction of rotation of the tray body and is provided with a limiting portion for limiting the mask plate from sliding from a front position of the sliding track to a rear position of the sliding track, the secondary containing groove is located at a first position and a second position arranged from back to front along the sliding track, the mask plate slides along the sliding track between the rear position and the front position to switch between covering the secondary containing groove at the first position and the secondary containing groove at the second position, the contact surface between the mask plate and the sliding track is a smooth sliding surface, so that the mask plate can slide from back to front on the sliding track under the action of inertia when the tray body is decelerated, and switch from covering the secondary containing groove at the first position to covering the secondary containing groove at the second position.

2. The sample holder for epitaxial growth of a double-layered growth substrate according to claim 1, characterized in that: The sliding track is an arc-shaped sliding track with the rotation center of the tray body as the center of the circle.

3. The sample holder for epitaxial growth of a double-layered growth substrate according to claim 1, characterized in that: The limiting portion includes a clamping groove which is arranged on the track surface of the sliding track at a position corresponding to the front sliding position and is concave-convexly matched with the supporting foot of the mask plate.

4. The sample holder for epitaxial growth of a double-layered growth substrate according to claim 1, characterized in that: The sliding rail includes a first sliding rail corresponding to the first position of the auxiliary accommodating groove and a second sliding rail corresponding to the second position of the auxiliary accommodating groove. The mask plate includes a covering body, a first supporting foot for supporting the covering body slidably on the track surface of the first sliding rail, and a second supporting foot for supporting the covering body slidably on the track surface of the second sliding rail. The height of the track surface of the first sliding rail is lower than the track surface of the second sliding rail.

5. The sample holder for epitaxial growth of a double-layered growth substrate according to claim 4, characterized in that: The height difference between the first supporting foot and the second supporting foot is equal to the height difference between the track surface of the first slide rail and the track surface of the second slide rail.

6. The sample holder for epitaxial growth of a double-layered growth substrate according to claim 4, characterized in that: A first slot is formed at one end of the first slide rail close to the second slide rail for limiting the first supporting foot of the mask plate that switches and slides to the front sliding position, and a second slot is formed at one end of the second slide rail away from the first slide rail for limiting the second supporting foot of the mask plate that switches and slides to the front sliding position, and the limiting portion includes the first slot and the second slot.

7. The sample holder for epitaxial growth of a double-layered growth substrate according to claim 1, characterized in that: The tray body is provided with a main accommodating area and a secondary accommodating area, the main accommodating groove is opened on the main accommodating area, the secondary accommodating groove is opened on the secondary accommodating area, the main accommodating area is arranged in the middle of the tray body, the secondary accommodating area extends from the edge of the tray body and is arranged around the main accommodating area, and the area of ​​the main accommodating groove is larger than the area of ​​the secondary accommodating groove.

8. The sample holder for epitaxial growth of a double-layered growth substrate according to claim 1, characterized in that: The auxiliary accommodating groove includes a first auxiliary accommodating groove located at a first position and a second auxiliary accommodating groove located at a second position.

9. The sample holder for epitaxial growth of a double-layered growth substrate according to claim 1, characterized in that: The surface roughness Ra of the contact surface between the mask plate and the sliding track is less than 10 nm.

10. The sample holder for epitaxial growth of a double-layered growth substrate according to claim 1, characterized in that: The mask plate can slide from the sliding rear position to the sliding front position under the action of inertia when the preset speed decreases to 0 within a preset time when the tray body rotates along a preset direction, thereby switching from covering the auxiliary accommodating groove at the first position to covering the auxiliary accommodating groove at the second position.

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