Epitaxial apparatus and semiconductor device

Abstract

The application provides an epitaxial device and a semiconductor device. The epitaxial device comprises an epitaxial process reaction cavity and a first laser control system. The epitaxial process reaction cavity is provided with a tray for carrying a substrate, and the epitaxial process reaction cavity comprises a first laser visible window. The first laser control system is used for emitting a first laser, and the first laser is emitted to the surface of the substrate carried by the tray after passing through the first laser visible window. During an epitaxial growth process, the area of the surface of the substrate which is not irradiated by the first laser forms a first growth surface, the first laser is used for interfering with the epitaxial growth process, and the area of the surface of the substrate which is irradiated by the first laser forms a second growth surface, the surface morphology of the second growth surface is different from that of the first growth surface, so that the epitaxial layer formed on the second growth surface is peeled off after high-temperature annealing, thereby forming a patterned epitaxial layer in the epitaxial process reaction cavity, and improving the electrical reliability of the semiconductor device.

Description

An epitaxial device and semiconductor device Technical Field

[0001] This application relates to the field of semiconductor technology, and more particularly to an epitaxial device and a semiconductor device. Background Technology

[0002] With the continuous development of semiconductor technology, semiconductor materials have been widely used in various fields. Compound semiconductors are semiconductor materials composed of two or more elements, such as GaAs, GaN, and SiC. Due to their advantages such as high power and high frequency, compound semiconductors hold an irreplaceable position in fields such as information communication, optoelectronic devices, and new energy vehicles.

[0003] In related technologies, compound semiconductor materials are used to fabricate semiconductor devices. The fabrication process is divided into epitaxial growth and patterning processes. Specifically, the substrate is first placed in the reaction chamber of an epitaxial device, and after the epitaxial growth process, an epitaxial layer is formed on the surface of the substrate. Then, the substrate is removed from the epitaxial device and subjected to patterning processes such as exposure and development, dry etching, and wet etching to obtain the pattern of the epitaxial layer. However, the patterning process is relatively complex and can easily introduce unstable factors. In particular, during the etching process, chemicals such as chlorine gas (Cl2) in dry etching and strong acids in wet etching can easily affect the step interfaces of the epitaxial layer, destroying the crystal at the step interfaces and forming defect centers. These defect centers have the ability to trap electrons, thus affecting the electrical reliability of the semiconductor device. Summary of the Invention

[0004] This application provides an epitaxial device and a semiconductor device to solve the problem in the related art where the complex patterning process affects the electrical reliability of semiconductor devices.

[0005] In a first aspect, embodiments of this application provide an epitaxial apparatus, which may include an epitaxial process reaction chamber and a first laser control system. The epitaxial process reaction chamber is provided with a tray for supporting at least one substrate, and the epitaxial process reaction chamber includes a first laser viewing window. The first laser control system emits a first laser beam, which passes through the first laser viewing window and is directed towards the surface of the substrate supported by the tray. The first laser beam is used to interfere with the epitaxial growth process. During the epitaxial growth process, the area of ​​the substrate surface not irradiated by the first laser forms a first growth surface, and the area of ​​the substrate surface irradiated by the first laser forms a second growth surface. The surface morphology of the second growth surface differs from that of the first growth surface, so that the epitaxial layer formed on the second growth surface is detached after high-temperature annealing, resulting in a patterned epitaxial layer. Here, the surface morphology refers to the microscopic morphology of the epitaxial layer surface, which can be characterized by parameters such as the surface roughness and crystal quality of the epitaxial layer.

[0006] In the epitaxial apparatus provided in this application embodiment, during the epitaxial growth process, a first laser can interfere with the epitaxial growth process, changing the surface morphology of the substrate. This causes the area of ​​the substrate surface irradiated by the first laser to form a second growth surface, while the area of ​​the substrate surface not irradiated by the first laser forms a first growth surface. Because the surface morphology of the second growth surface differs from that of the first growth surface, the crystal quality of the epitaxial layer formed at the second growth surface is poor, causing the epitaxial layer formed at the second growth surface to detach after annealing, thus obtaining a patterned epitaxial layer. Therefore, in this application embodiment, a patterned epitaxial layer can be formed within the epitaxial process reaction chamber, eliminating the need to remove the substrate from the epitaxial process reaction chamber and then use other equipment for patterning. This avoids the chemical substances in dry etching or wet etching processes affecting the step interfaces of the epitaxial layer, effectively protecting the steps of the epitaxial layer and improving the electrical reliability of the semiconductor device.

[0007] In actual process, the substrate surface can be irradiated with a first laser before the epitaxial growth process is performed. Alternatively, the epitaxial growth process can be performed simultaneously with the irradiation of the substrate surface with a first laser.

[0008] In some embodiments of this application, a heater and a support disk may also be provided within the epitaxial process reaction chamber. The heater is located on the side of the tray opposite to the first laser viewing window. The heater can provide temperature during the epitaxial growth process and the high-temperature annealing process. The support disk is used to support the tray. Optionally, the heater can be disposed inside the support disk to provide a more uniform temperature to the substrate supported by the tray.

[0009] In this embodiment, the first laser control system is placed outside the epitaxial process reaction cavity, which can prevent high temperature damage to the first laser control system during the epitaxial growth process and high temperature annealing process, and ensure that the first laser control system has good functionality.

[0010] In some embodiments of this application, the first laser control system described above may include a first laser generator and a photomask. The photomask includes a light-transmitting area and a light-blocking area. The first laser generator emits a first laser beam and directs the first laser beam toward the photomask, so that the first laser beam passes through the light-transmitting area of ​​the photomask and then strikes the surface of the substrate carried by the tray.

[0011] By setting a mask in the first laser control system, the light-blocking area in the mask blocks light, so the first laser can only pass through the light-transmitting area of ​​the mask to reach the substrate. Since the area of ​​the substrate surface not irradiated by the first laser forms the first growth surface, and the area of ​​the substrate surface irradiated by the first laser forms the second growth surface, the light-blocking area in the mask corresponds to the area of ​​the first growth surface, and the light-transmitting area in the mask corresponds to the area of ​​the second growth surface. Furthermore, the pattern of the light-blocking area of ​​the mask is consistent with the pattern of the epitaxial layer to be formed. In specific implementations, the patterns of the light-transmitting and light-blocking areas in the mask can be set according to the pattern of the epitaxial layer to be formed. The mask can be detachably set in the first laser control system so that the mask can be replaced according to the pattern of the epitaxial layer to be formed.

[0012] In some embodiments of this application, the first laser control system may further include: a second laser generator, a laser modulator, and a first reflected light receiver. The second laser generator emits a second laser beam with a wavelength greater than that of the first laser. For example, the wavelength of the first laser can be set to less than 365 nm; for example, the first laser can be an ultraviolet laser or an extreme ultraviolet laser, and the power of the first laser can be set to greater than 1 W. The wavelength of the second laser can be set to greater than 365 nm; for example, the second laser can be green or blue light, and the power of the second laser can be set to less than 1 W. A shorter wavelength for the first laser allows it to have higher energy, enabling it to influence the surface morphology of the substrate when it irradiates the substrate surface. A longer wavelength for the second laser allows it to have lower energy, ensuring that it does not affect the surface morphology of the substrate when it irradiates the substrate surface. Therefore, the second laser is not absorbed by the substrate surface, meaning it can be reflected by the substrate.

[0013] A laser modulator receives a first laser beam emitted from a first laser generator and a second laser beam emitted from a second laser generator. It directs the modulated first and second laser beams toward a photomask so that they pass through the light-transmitting area of ​​the photomask and then strike the surface of the substrate held on a tray. Optionally, the laser modulator can adjust the power and frequency of the first and second laser beams. The first laser beam can interfere with the epitaxial growth process, causing the irradiated area of ​​the substrate surface to form a second growth surface. Because the first laser beam interacts with the substrate surface, it is absorbed by the substrate surface. The second laser beam, with its lower energy, does not interact with the substrate and is therefore reflected by the substrate surface, resulting in the first reflected light.

[0014] The first reflected light receiver is used to receive the first reflected light reflected from the surface of the substrate, process the first reflected light to remove any residual first laser light, obtain a reflected signal corresponding to the second laser light, and feed the obtained reflected signal back to the laser modulator.

[0015] The laser modulator is also used to determine the surface roughness of the second growth surface based on the reflected signal, and to readjust the first laser according to the determined surface roughness. For example, the power and frequency of the first laser can be adjusted until the surface roughness of the second growth surface reaches a set threshold. Surface roughness characterizes the surface morphology. Because the first laser has high energy, it can affect the surface roughness of the substrate when it irradiates the substrate surface. Furthermore, different surface roughnesses of the substrate result in different intensities of the first reflected light reflected from the substrate surface. Therefore, the surface roughness of the second growth surface can be obtained from the reflected signal obtained from the first reflected light receiver and a predetermined correspondence between the reflected signal and the surface roughness. Then, the first laser is readjusted according to the determined surface roughness. If the surface roughness does not reach the set threshold, the intensity of the first laser is increased to increase the surface roughness of the second growth surface, ultimately bringing the surface roughness of the second growth surface to the set threshold.

[0016] In this embodiment, a second laser generator, a laser modulator, and a first reflected light receiver are set up to form a feedback loop. The first reflected light obtained after the second laser is directed onto the substrate surface is used to reflect the surface roughness of the second growth surface according to the principle of light interference. Then, the first laser is adjusted according to the obtained surface roughness. For example, the power and frequency of the first laser T1 can be adjusted so that the roughness of the second growth surface reaches a set value, thereby improving the patterning effect of the epitaxial layer.

[0017] In some embodiments of this application, the first laser control system may further include a first condensing lens and a first beam splitter. The first condensing lens is located on the output side of the laser modulator and is used to converge the first and second lasers emitted from the laser modulator, and direct the converged first and second lasers toward the first beam splitter. The first beam splitter transmits the converged first and second lasers from the first condensing lens to a photomask, and reflects the first reflected light from the substrate surface to a first reflected light receiver. In other words, the first and second lasers emitted from the first condensing lens, as well as the first reflected light from the substrate surface, can all be transmitted through the first beam splitter, thereby simplifying the optical path in the first laser control system, making the optical path in the first laser control system more compact, and reducing the size of the first laser control system.

[0018] The epitaxial device described in this embodiment may further include: a first rotating shaft connected to a tray, the first rotating shaft being used to drive the tray to rotate. The surface of the tray is provided with multiple carrier disks, the carrier disks being used to carry a substrate; the multiple carrier disks are arranged along at least one annular line on the surface of the tray, the annular line being symmetrical about the first rotating shaft as a central axis; the carrier disks are connected to the tray via a second rotating shaft, the second rotating shaft being used to drive the carrier disks to rotate. In specific implementations, the carrier disks and the second rotating shaft may be located on the surface of the tray, or a groove may be provided on the surface of the tray, embedding the second rotating shaft and the carrier disks into the groove, thereby reducing the total thickness of the tray and the carrier disks.

[0019] In some embodiments of this application, the epitaxial apparatus may further include a second laser control system, and the epitaxial process reaction cavity may further include a second laser viewing window. The second laser control system is used to emit a third laser, which passes through the second laser viewing window and then strikes the surface of the tray. The surface of the tray is provided with a first mark; during tray rotation, the path of the third laser on the tray passes through the first mark. In this way, the time and pattern of the third laser passing through the first mark can be determined based on the reflected light of the third laser, and combined with the positional relationship between the target substrate to be patterned and the first mark, the first laser emitted by the first laser control system can be controlled to strike the target substrate. Optionally, a pit can be provided on the surface of the tray, and the pit can be used as the first mark. Alternatively, the first mark can be provided in other ways, for example, a protrusion can be provided on the surface of the tray as the first mark.

[0020] In this embodiment, the second laser control system is placed outside the epitaxial process reaction cavity, which can prevent high temperature damage to the second laser control system during the epitaxial growth process and high temperature annealing process, and ensure that the second laser control system has good functionality.

[0021] In some embodiments of this application, the second laser control system may include: a third laser generator, a second reflected light receiver, a photoelectric signal converter, and a rotation axis controller. The third laser generator emits a third laser beam, which passes through the second laser viewing window and is directed onto the surface of the tray. The second reflected light receiver receives the second reflected light reflected from the surface of the tray after the third laser beam strikes it, and transmits the second reflected light to the photoelectric signal converter. The photoelectric signal converter converts the received second reflected light into a reflected electrical signal and transmits the reflected electrical signal to the rotation axis controller. The rotation axis controller controls the rotation of the first rotation axis during the epitaxial growth process to rotate the tray, thereby ensuring a more uniform thickness of the formed epitaxial layer. Optionally, the rotation axis controller can drive the first rotation axis to rotate via a motor.

[0022] Furthermore, due to the high rotation speed of the tray, a rotation axis controller is needed to reduce the tray's speed in order for the first laser to be directed towards the surface of the target substrate. The rotation axis controller is also used to determine the time and period of the third laser passing the first mark based on the reflected electrical signal, and, combined with the positional relationship between the target substrate and the first mark, adjust the rotation speed of the first axis to reduce the tray's rotation speed to a first speed value, so that the first laser emitted by the first laser controller can be directed towards the surface of the target substrate. Optionally, the first speed value can be zero or other values. The target substrate can be a substrate for which a patterned epitaxial layer needs to be formed. The positional relationship between the target substrate and the first mark can be the angular relationship between the target substrate and the first mark about the first rotation axis, or it can be the distance between the target substrate and the first mark, or it can be characterized by other parameters, which are not limited here.

[0023] During the tray rotation, the path of the third laser on the tray passes through the first mark. Due to differences in material and shape between the first mark and other locations on the tray, the intensity of the second reflected light obtained when the third laser strikes the first mark differs from the intensity of the second reflected light obtained when the third laser strikes other locations outside the first mark. Therefore, the time and period of the third laser passing through the first mark can be determined based on the second reflected light. Based on the patterns of the optical and electrical signals of the second reflected light, and combined with the positional relationship between the target substrate and the first mark, the first laser emitted by the first laser controller is controlled to accurately strike the surface of the target substrate. Furthermore, the accuracy of controlling the first laser to strike the surface of the target substrate can be within 1 μm.

[0024] In practical implementation, when the tray rotates at the first speed value, the frequency of the first laser emitted by the first laser controller can be controlled so that the first laser is emitted when the first laser controller passes the position of the target substrate, and the first laser is not emitted when the first laser controller does not pass the position of the target substrate.

[0025] Furthermore, in embodiments of this application, the substrate carried by the carrier disk includes a second mark, and the photomask has alignment marks. The spindle controller is also used to adjust the rotation speed of the second spindle to reduce the rotation speed of the carrier disk to a second speed value, so that the second mark on the target substrate is aligned with the alignment marks on the photomask. Optionally, the second speed value can be zero or other values. The spindle controller can adjust the rotation speed of the second spindle via airflow.

[0026] Since the substrate includes the second mark, during the rotation of the carrier disk, the path of the third laser on the carrier disk can pass through the surface of both the carrier disk and the substrate. Due to the differences in material and shape between the carrier disk and the substrate, the intensities of the second reflected light received by the third laser on the carrier disk and the substrate are different. Therefore, the pattern of the third laser passing through the carrier disk and the substrate can be determined based on the second reflected light. According to the patterns of the optical and electrical signals of the second reflected light, the alignment of the second mark on the target substrate with the alignment mark on the mask can be controlled, and the alignment accuracy can be controlled within 1 μm.

[0027] In a specific implementation, the aforementioned second laser control system may further include: an optical lens, a second beam splitter, and a second condensing lens. The optical lens is located on the light-emitting side of the third laser generator and is used to transmit the third laser emitted by the third laser generator to the second beam splitter. The second beam splitter is used to transmit the received third laser to the second condensing lens, receive the second reflected light emitted from the second condensing lens, and transmit the second reflected light to a second reflected light receiver. The second condensing lens is used to converge the third laser and transmit the converged third laser to the surface of the tray, receive the second reflected light reflected after the third laser strikes the surface of the tray, and transmit the second reflected light to the second beam splitter. By setting the second beam splitter, the light emitted from the optical lens can be transmitted to the second condensing lens, and the second reflected light emitted from the third condensing lens can also be transmitted to the second reflected light receiver, thereby simplifying the optical path of the second laser control system, making the optical path of the second laser control system more compact, and reducing the size of the second laser control system.

[0028] In some embodiments of this application, a plurality of carrier disks are arranged on the surface of a tray along at least two annular lines. A second laser viewing window is a strip-shaped structure extending radially along the tray, the position of which corresponds to at least two annular lines, and the length of the second laser viewing window is greater than the width of at least two carrier disks. A second laser control system is movable along the extending direction of the second laser viewing window. Thus, by controlling the movement of the second laser control system, the third laser emitted by the second laser control system can be directed towards the substrate at different locations, facilitating the alignment of the substrate with the mask at different locations.

[0029] Secondly, embodiments of this application also provide a method for fabricating a semiconductor device, which may include:

[0030] Place the substrate on the tray in the epitaxial process reaction chamber of any of the above-mentioned epitaxial devices;

[0031] During the epitaxial growth process, the first laser control system emits a first laser, which passes through the first laser viewing window and is directed at the surface of the substrate supported by the tray, so that the first laser interferes with the epitaxial growth process; the area of ​​the substrate surface not irradiated by the first laser forms a first growth surface; the area of ​​the substrate surface irradiated by the first laser forms a second growth surface; the surface morphology of the second growth surface is different from that of the first growth surface.

[0032] The epitaxial layer formed by the epitaxial growth process is subjected to high-temperature annealing to remove the epitaxial layer formed on the second growth surface, thereby obtaining a patterned epitaxial layer.

[0033] In the fabrication method provided in this application embodiment, during the epitaxial growth process, a first laser control system emits a first laser. The first laser can interfere with the epitaxial growth process, changing the surface morphology of the substrate. The area of ​​the substrate surface irradiated by the first laser forms a second growth surface, while the area of ​​the substrate surface not irradiated by the first laser forms a first growth surface. Because the surface morphology of the second growth surface differs from that of the first growth surface, the crystal quality of the epitaxial layer formed at the second growth surface is poor, causing the epitaxial layer formed at the second growth surface to detach after annealing, thus obtaining a patterned epitaxial layer. Therefore, in this application embodiment, a patterned epitaxial layer can be formed within the epitaxial process reaction chamber, eliminating the need to remove the substrate from the epitaxial process reaction chamber and then perform the patterning process using other equipment. This avoids the chemical substances in dry etching or wet etching processes affecting the step interfaces of the epitaxial layer, effectively protecting the steps of the epitaxial layer and improving the electrical reliability of the semiconductor device.

[0034] In specific implementation, the control of the first laser system emitting the first laser during the epitaxial growth process may include:

[0035] During the epitaxial growth process, the first laser generator in the first laser control system emits a first laser and the second laser generator emits a second laser.

[0036] The laser modulator in the first laser control system adjusts the power and frequency of the first and second lasers;

[0037] The first reflected light receiver in the first laser control system receives the first reflected light reflected from the surface of the substrate, processes the first reflected light to obtain a reflected signal corresponding to the second laser, and feeds the obtained reflected signal back to the laser modulator.

[0038] The laser modulator determines the surface roughness of the second growth surface based on the reflected signal, and readjusts the power and frequency of the first laser based on the determined surface roughness until the surface roughness of the second growth surface reaches the set threshold.

[0039] In this embodiment, the first laser generator in the first laser control system emits a first laser and the second laser generator emits a second laser. By acquiring the first reflected light obtained after the second laser is directed onto the substrate surface, the surface roughness of the second growth surface is reflected according to the principle of light interference. Then, the power and frequency of the first laser are adjusted according to the obtained surface roughness so that the roughness of the second growth surface reaches the set value, thereby improving the patterning effect of the epitaxial layer.

[0040] In practical applications, in some embodiments of this application, the above-described manufacturing method may further include:

[0041] The third laser generator in the second laser control system emits a third laser, which passes through the second laser viewing window and is directed onto the surface of the tray.

[0042] The photoelectric signal converter in the second laser control system converts the second reflected light received from the surface of the tray into a reflected electrical signal, and transmits the reflected electrical signal to the shaft controller.

[0043] The control shaft controller controls the rotation of the first shaft to drive the tray to rotate;

[0044] The control axis controller determines the time and period of the third laser passing through the first mark on the tray based on the reflected electrical signal, and adjusts the rotation speed of the first axis in combination with the positional relationship between the target substrate and the first mark, so that the rotation speed of the tray is reduced to the first speed value, so that the first laser emitted by the first laser controller is directed toward the surface of the target substrate; wherein, the target substrate can be a substrate for which a patterned epitaxial layer needs to be formed.

[0045] During the tray rotation, the path of the third laser on the tray passes through the first mark. Due to differences in material and shape between the first mark and other locations on the tray, the intensity of the second reflected light obtained when the third laser strikes the first mark differs from the intensity of the second reflected light obtained when the third laser strikes other locations outside the first mark. Therefore, the timing and pattern of the third laser passing through the first mark can be determined based on the second reflected light. The patterns of the optical and electrical signals of the second reflected light, combined with the positional relationship between the target substrate and the first mark, control the first laser emitted by the first laser controller to be directed towards the surface of the target substrate, thus ensuring that the first laser accurately strikes the surface of the target substrate.

[0046] Furthermore, the manufacturing method provided in the embodiments of this application may also include:

[0047] The control spindle controller adjusts the rotation speed of the second spindle to reduce the rotation speed of the carrier disk to a second speed value so that the second mark on the target substrate is aligned with the alignment mark on the mask.

[0048] During the rotation of the carrier disk, the path of the third laser on the carrier disk can pass through the surface of the carrier disk and the surface of the substrate. Due to the differences in materials and shapes between the carrier disk and the substrate, the intensity of the second reflected light obtained by the third laser when it is directed at the carrier disk and the substrate is different. Therefore, the pattern of the third laser passing through the carrier disk and the substrate can be determined based on the second reflected light. Thus, the alignment of the second mark on the target substrate with the alignment mark on the mask can be controlled.

[0049] The implementation of the manufacturing method provided in this application embodiment can refer to the implementation of any of the above-described epitaxial devices, and the repeated parts will not be described in detail.

[0050] Thirdly, embodiments of this application also provide a semiconductor device fabricated using any of the aforementioned epitaxial equipment. Since the epitaxial equipment provided in this application can form a patterned epitaxial layer within the epitaxial process reaction chamber, eliminating the need to remove the substrate from the reaction chamber and then perform patterning using other equipment, it avoids the influence of chemical substances in dry etching or wet etching processes on the step interfaces of the epitaxial layer, effectively protecting the steps of the epitaxial layer. Therefore, the semiconductor device provided in this application has high electrical reliability. Attached Figure Description

[0051] Figure 1 is a schematic diagram of the structure of the epitaxial device provided in an embodiment of this application;

[0052] Figures 2 to 4 are schematic diagrams of the structure during the epitaxial growth process in the embodiments of this application;

[0053] Figure 5 is a schematic diagram of the structure of the first laser control system in the embodiment of this application;

[0054] Figure 6 is a schematic diagram of the planar structure of the tray in an embodiment of this application;

[0055] Figure 7 is a cross-sectional view of the pallet in Figure 6 at one of the carrying trays;

[0056] Figure 8 is a cross-sectional view of the first marked location in Figure 6;

[0057] Figure 9 is a schematic diagram of the planar structure of a tray carrying multiple substrates in an embodiment of this application;

[0058] Figure 10 is a schematic diagram of the planar structure of the substrate in an embodiment of this application;

[0059] Figure 11 is a schematic diagram of another planar structure of the substrate in an embodiment of this application;

[0060] Figure 12 is a schematic diagram of the structure of the second laser control system in an embodiment of this application;

[0061] Figure 13 shows the waveforms of the optical and electrical signals of the second reflected light obtained during the tray rotation process;

[0062] Figure 14 shows the waveforms of the optical and electrical signals of the second reflected light obtained during the rotation of the carrier disk;

[0063] Figure 15 is a schematic diagram of another planar structure of the tray in an embodiment of this application;

[0064] Figure 16 is a flowchart of the manufacturing method provided in the embodiment of this application.

[0065] Figure label:

[0066] 10-Epiaxial process reaction chamber; 11-Tray; 111-Carrier disk; 112-Second rotating shaft; 12-Substrate; 121a, 121b, 121c, 121c′, 121d, 121d′-Epiaxial layers; 122-Buffer layer; 13-Heater; 14-Support disk; 15-First rotating shaft; 20-First laser control system; 201-First laser generator; 202-Second laser generator; 203-Laser modulator; 204-First reflected light receiver; 205-First focusing lens; 206-First beam splitter; 30-Second laser control system; 301-Third laser Generator; 302-Second reflected light receiver; 303-Photoelectric signal converter; 304-Rotation controller; 305-Optical lens; 306-Second beam splitter; 307-Second condenser lens; U1-First laser viewing window; U2-Second laser viewing window; S1-First growth surface; S2-Second growth surface; T1-First laser; T2-Second laser; T3-Third laser; Q1, Q2-Steps; M-Mask; M1-Transmitting area; M2-Shielding area; R1-First mark; R2-Second mark; L-Circular line; Y1-First reflected light; Y2-Second reflected light. Detailed Implementation

[0067] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0068] It should be noted that the same reference numerals in the accompanying drawings of this application denote the same or similar structures, and therefore repeated descriptions of them will be omitted. Terms expressing position and direction described in this application are illustrative based on the accompanying drawings, but may be modified as needed, and all such modifications are included within the scope of protection of this application. The accompanying drawings of this application are for illustrating relative positional relationships only and do not represent actual scale.

[0069] This application provides an epitaxial apparatus and a semiconductor device. The epitaxial apparatus can be a metal-organic chemical vapor deposition (MOCVD) apparatus, or a molecular beam epitaxy (MBE) apparatus, etc. This epitaxial apparatus can be used to fabricate various types of semiconductor devices, such as high electron mobility transistors (HMTs) and metal-oxide-semiconductor field-effect transistors (MOSFETs). In practical applications, the epitaxial apparatus provided in this application can also be used to fabricate other types of semiconductor devices, which will not be listed here.

[0070] Figure 1 is a schematic diagram of the epitaxial device provided in an embodiment of this application. As shown in Figure 1, the epitaxial device provided in this embodiment may include an epitaxial process reaction chamber 10 and a first laser control system 20. The epitaxial process reaction chamber 10 is provided with a tray 11 for supporting at least one substrate 12, and the epitaxial process reaction chamber 10 includes a first laser viewing window U1. The first laser control system 20 is used to emit a first laser T1, and after the first laser T1 passes through the first laser viewing window U1, it is directed towards the surface of the substrate 12 supported by the tray 11. The first laser T1 is used to interfere with the epitaxial growth process. During the epitaxial growth process, the area of ​​the surface of the substrate 12 that is not irradiated by the first laser T1 forms a first growth surface. The area of ​​the surface of the substrate 12 that is irradiated by the first laser T1 forms a second growth surface. The surface morphology of the second growth surface is different from that of the first growth surface, so that the epitaxial layer formed on the second growth surface is detached after high-temperature annealing to obtain a patterned epitaxial layer. Here, the surface morphology refers to the microscopic morphology of the surface of the epitaxial layer, which can be characterized by parameters such as the surface roughness and crystal quality of the epitaxial layer.

[0071] In the epitaxial apparatus provided in this application embodiment, during the epitaxial growth process, a first laser can interfere with the epitaxial growth process, changing the surface morphology of the substrate. This causes the area of ​​the substrate surface irradiated by the first laser to form a second growth surface, while the area of ​​the substrate surface not irradiated by the first laser forms a first growth surface. Because the surface morphology of the second growth surface differs from that of the first growth surface, the epitaxial layer formed at the second growth surface has poor crystal quality, poor stability, and is easily decomposed. Consequently, the epitaxial layer formed at the second growth surface decomposes and detaches after annealing, resulting in a patterned epitaxial layer. Therefore, in this application embodiment, a patterned epitaxial layer can be formed within the epitaxial process reaction chamber, eliminating the need to remove the substrate from the reaction chamber and then perform the patterning process using other equipment. This avoids the chemical substances in dry etching or wet etching processes affecting the step interfaces of the epitaxial layer, effectively protecting the steps of the epitaxial layer and improving the electrical reliability of the semiconductor device.

[0072] Figures 2 to 4 are schematic diagrams of the epitaxial growth process in the embodiments of this application. As shown in Figure 2, the area of ​​the substrate 12 surface irradiated by the first laser T1 forms a second growth surface S2, which can be a non-polar surface or a semi-polar surface. The area of ​​the substrate 12 surface not irradiated by the first laser T1 forms a first growth surface S1. In specific implementations, before the first laser T1 irradiates the surface of the substrate 12, a buffer layer 122, an epitaxial layer 121a, and an epitaxial layer 121b can be formed on the surface of the substrate 12.

[0073] As shown in Figure 3, during the epitaxial growth process, the products resulting from the reaction between reactant A and reactant B are deposited layer by layer onto the surface of substrate 12. The remaining gaseous products C are discharged with the carrier gas, which can be one of H2, N2, O2, or Ar, or a mixture of at least two of these gases. Epitaxial growth continues on the first epitaxial growth surface S1 and the second growth surface S2. Epitaxial layers 121c and 121d are formed on the first epitaxial growth surface S1, and epitaxial layers 121c′ and 121d′ are formed on the second epitaxial growth surface S2. Epitaxial layers 121c′ and 121c are epitaxial layers of the same family, and epitaxial layers 121d′ and 121d are epitaxial layers of the same family.

[0074] However, due to the different surface morphologies of the second growth surface S2 and the first growth surface S1, the crystal growth directions at the second growth surface S2 and the first growth surface S1 are different. This results in poorer crystal quality and thinner thickness at the second growth surface S2. Furthermore, the epitaxial layer formed at the second growth surface S2 is generally a polycrystalline or amorphous structure. Therefore, the crystal orientation and crystal quality of epitaxial layers 121c′, 121d′, 121c, and 121d differ greatly, causing epitaxial layers 121c′ and 121d′ to detach from the second growth surface S2 after subsequent high-temperature annealing. The temperature during the high-temperature annealing process can be greater than or equal to 800℃. As shown in Figure 4, after high-temperature annealing, the formed epitaxial layers 121c and 121d have steps Q1 and Q2, respectively, thus obtaining a patterned epitaxial layer. Since the structure shown in Figure 4 has not undergone patterning processes such as dry etching or wet etching, steps Q1 and Q2 in the structure shown in Figure 4 will not be damaged by chemical substances, resulting in a semiconductor device with good electrical reliability.

[0075] In actual process, the substrate surface can be irradiated with a first laser before the epitaxial growth process is performed. Alternatively, the epitaxial growth process can be performed simultaneously with the irradiation of the substrate surface with a first laser.

[0076] As shown in Figure 1, a heater 13 and a support disk 14 may also be provided in the epitaxial process reaction chamber 10. The heater 13 is located on the side of the tray 11 opposite to the first laser viewing window U1. The heater 13 can provide the temperature during the epitaxial growth process and the high-temperature annealing process. The support disk 14 is used to support the tray 11. Optionally, the heater 13 can be placed inside the support disk 14 to provide a more uniform temperature to the substrate 12 carried by the tray 11.

[0077] In this embodiment, the first laser control system 20 is disposed outside the epitaxial process reaction cavity 10, which can prevent high temperature damage to the first laser control system 20 during the epitaxial growth process and high temperature annealing process, and ensure that the first laser control system 20 has good functionality.

[0078] Figure 5 is a schematic diagram of the structure of the first laser control system in this embodiment of the application. As shown in Figure 5, the first laser control system 20 may include a first laser generator 201 and a mask M. The mask M includes a light-transmitting area M1 and a light-blocking area M2. The first laser generator 201 emits a first laser T1 and directs it toward the mask M, so that the first laser T1 passes through the light-transmitting area M1 of the mask M and then strikes the surface of the substrate 12 supported by the tray. By setting the mask M in the first laser control system 20, the light-blocking area M2 in the mask M blocks the light, thus the first laser T1 can only pass through the light-transmitting area M1 of the mask M and strike the substrate 12. Since the area of ​​the substrate 12 not irradiated by the first laser T1 forms the first growth surface S1, and the area of ​​the substrate 12 irradiated by the first laser T1 forms the second growth surface S2, the light-blocking area M2 in the mask M corresponds to the area of ​​the first growth surface S1, and the light-transmitting area M1 in the mask M corresponds to the area of ​​the second growth surface S2. Furthermore, the pattern of the light-blocking region M2 of the photomask M is consistent with the pattern of the epitaxial layer to be formed. In specific implementation, the patterns of the light-transmitting region M1 and the light-blocking region M2 in the photomask M can be set according to the pattern of the epitaxial layer to be formed. The photomask M can be detachably installed in the first laser control system 20 so that the photomask M can be replaced according to the pattern of the epitaxial layer to be formed.

[0079] Optionally, the first laser emitted by the first laser generator can be a single point or multiple points, and the first laser generator can emit the first laser in continuous mode or pulsed mode. The first laser generator can be fixed in place.

[0080] Referring again to Figure 5, in some embodiments of this application, the first laser control system 20 may further include: a second laser generator 202, a laser modulator 203, and a first reflected light receiver 204. The second laser generator 202 emits a second laser T2, the wavelength of which is greater than the wavelength of the first laser T1. For example, the wavelength of the first laser T1 can be set to less than 365 nm; for example, the first laser T1 can be an ultraviolet laser or an extreme ultraviolet laser, and its power can be set to greater than 1 W. The wavelength of the second laser T2 can be set to greater than 365 nm; for example, the second laser T2 can be green light or blue light, and its power can be set to less than 1 W. The shorter wavelength of the first laser T1 allows it to have higher energy, enabling it to influence the surface morphology of the substrate 12 when it irradiates the surface of the substrate 12. The second laser T2 has a longer wavelength, which allows it to have lower energy. This ensures that when the second laser T2 irradiates the surface of the substrate 12, it does not affect the surface morphology of the substrate 12. Consequently, the second laser T2 is not absorbed by the surface of the substrate 12, meaning that the second laser T2 can be reflected by the substrate 12.

[0081] The laser modulator 203 receives the first laser T1 emitted from the first laser generator 201 and the second laser T2 emitted from the second laser generator 202, and directs the modulated first laser T1 and second laser T2 toward the mask M, so that the first laser T1 and second laser T2 pass through the light-transmitting area M1 of the mask M and are directed toward the surface of the substrate 12 carried by the tray. Optionally, the laser modulator 203 can adjust the power and frequency of the first laser T1 and the second laser T2. The first laser T1 can interfere with the epitaxial growth process, causing the irradiated area of ​​the substrate 12 to form a second growth surface S2. Because the first laser T1 interacts with the surface of the substrate 12, it is absorbed by the surface of the substrate 12. The second laser T2 has lower energy and does not interact with the substrate 12. Therefore, the second laser T2 is reflected by the surface of the substrate 12, resulting in the first reflected light Y1.

[0082] The first reflected light receiver 204 is used to receive the first reflected light Y1 reflected from the surface of the substrate 12, process the first reflected light Y1 to remove the first laser T1 that may remain in the first reflected light Y1, obtain the reflected signal corresponding to the second laser T2, and feed the obtained reflected signal back to the laser modulator 203.

[0083] The laser modulator 203 is also used to determine the surface roughness of the second growth surface S2 based on the reflection signal, and to readjust the first laser T1 according to the determined surface roughness. For example, the power and frequency of the first laser T1 can be adjusted until the surface roughness of the second growth surface S2 reaches a set threshold. Surface roughness characterizes the surface morphology. Since the first laser T1 has high energy, it can affect the surface roughness of the substrate 12 when it irradiates the surface of the substrate 12. Furthermore, different surface roughnesses of the substrate 12 result in different intensities of the first reflected light Y1 reflected from the surface of the substrate 12. Therefore, the surface roughness of the second growth surface S2 can be obtained from the reflection signal obtained by the first reflected light receiver 204 and the predetermined correspondence between the reflection signal and the surface roughness. Then, the first laser T1 is readjusted according to the determined surface roughness. If the surface roughness does not reach the set threshold, the first laser T1 is readjusted to increase its intensity, thereby increasing the surface roughness of the second growth surface S2, until the surface roughness of the second growth surface S2 finally reaches the set threshold.

[0084] In this embodiment, by setting a second laser generator 202, a laser modulator 203, and a first reflected light receiver 204, and forming a feedback loop, the first reflected light Y1 obtained after the second laser T2 is directed onto the surface of the substrate 12 is used to reflect the surface roughness of the second growth surface S2 according to the principle of light interference. Then, the first laser T1 is adjusted according to the obtained surface roughness. For example, the power and frequency of the first laser T1 can be adjusted so that the roughness of the second growth surface S2 reaches a set value, thereby improving the patterning effect of the epitaxial layer.

[0085] Referring again to Figure 5, the first laser control system 20 may further include a first condenser lens 205 and a first beam splitter 206. The first condenser lens 205 is located on the light-emitting side of the laser modulator 203, and is used to converge the first laser T1 and the second laser T2 emitted from the laser modulator 203, and direct the converged first laser T1 and the second laser T2 toward the first beam splitter 206. The first beam splitter 206 is used to transmit the converged first laser T1 and the second laser T2 from the first condenser lens 205 to the mask M, and to reflect the first reflected light Y1 reflected from the surface of the substrate 12 to the first reflected light receiver 204. In other words, the first laser T1 and the second laser T2 emitted from the first condenser lens 205, as well as the first reflected light Y1 reflected from the surface of the substrate 12, can all be transmitted through the first beam splitter 205, thereby simplifying the optical path in the first laser control system 20, making the optical path in the first laser control system 20 more compact, and reducing the size of the first laser control system 20.

[0086] As shown in Figure 1, the extended device described in this embodiment may further include a first rotating shaft 15 connected to the tray 11, the first rotating shaft 15 being used to drive the tray 11 to rotate. Optionally, the first rotating shaft 15 may be fixedly connected to the support plate 14, and the first rotating shaft 15 may rotate under the drive of a motor to drive the support plate 14 to rotate, thereby driving the tray 11 to rotate.

[0087] Figure 6 is a schematic diagram of the planar structure of the tray in an embodiment of this application. As shown in Figure 6, the surface of the tray 11 is provided with a plurality of bearing disks 111, which are used to support a substrate (not shown in the figure). The plurality of bearing disks 111 are arranged along at least one annular line L on the surface of the tray 11, with the annular line L as the central axis of symmetry about the first axis of rotation 15. Figure 6 illustrates an example of the plurality of bearing disks 111 being arranged along one annular line L on the surface of the tray 11. In specific implementation, the plurality of bearing disks 111 can also be arranged along two or more annular lines L. That is to say, the surface of the tray 11 can also be provided with multiple rings of bearing disks 111.

[0088] Figure 7 is a cross-sectional view of the pallet at one of the support trays in Figure 6. Referring to Figures 6 and 7, the support tray 111 is connected to the pallet 11 via a second rotating shaft 112, which drives the support tray 111 to rotate. Figure 7 illustrates an example where the support tray 111 and the second rotating shaft 112 are located on the surface of the pallet 11. In practical implementation, a groove can be provided on the surface of the pallet 11, and the second rotating shaft 112 and the support tray 111 can be embedded into the groove, thereby reducing the total thickness of the pallet 11 and the support tray 111.

[0089] During the epitaxial growth process, in order to make the formed epitaxial layer more uniform, the tray 11 can be rotated by the first rotating shaft 15. For example, the tray 11 can be rotated in the direction shown by arrow P1 in the figure, and the rotation speed of the tray 11 can be around 1200 r / min. In addition, the carrier plate 111 can also be rotated by the second rotating shaft 112. For example, the carrier plate 111 can be rotated in the direction shown by arrow P2 in the figure.

[0090] In another embodiment of this application, as shown in FIG1, the epitaxial device may further include a second laser control system 30. The epitaxial process reaction cavity 10 may further include a second laser viewing window U2. The second laser control system 30 is used to emit a third laser T3, and to make the third laser T3 pass through the second laser viewing window U2 and then be directed toward the surface of the tray 11. As shown in FIG6, the surface of the tray 11 is provided with a first mark R1. During the rotation of the tray 11, the path of the third laser T3 on the tray 11 passes through the first mark R1. In this way, the time and pattern of the third laser T3 passing through the first mark R1 can be determined according to the reflected light of the third laser T3, and combined with the positional relationship between the target substrate to be patterned and the first mark R1, the first laser emitted by the first laser control system can be controlled to be directed toward the target substrate. FIG6 illustrates an example with a first mark R1 on the surface of the tray 11. In specific implementation, the number of first marks R1 can be set according to actual needs, and is not limited here.

[0091] Figure 8 is a cross-sectional view of the first mark in Figure 6. As shown in Figure 8, a recess can be provided on the surface of the tray 11, and the recess can be used as the first mark R1. Alternatively, the first mark R1 can be provided in other ways, for example, a protrusion can be provided on the surface of the tray 11 as the first mark R1.

[0092] In this embodiment, the second laser control system 30 is disposed outside the epitaxial process reaction cavity 10, which can prevent high temperature damage to the second laser control system 30 during the epitaxial growth process and high temperature annealing process, and ensure that the second laser control system 30 has good functionality.

[0093] Figure 9 is a schematic planar structure diagram of a tray supporting multiple substrates in an embodiment of this application. As shown in Figure 9, the substrate 12 supported by the carrier tray 111 includes a second mark R2, which can be aligned with the mask during the epitaxial growth process. Figure 10 is a schematic planar structure diagram of the substrate in an embodiment of this application. As shown in Figure 10, a flat edge can be provided at the edge of the substrate 12 as the second mark R2. Figure 11 is another schematic planar structure diagram of the substrate in an embodiment of this application. As shown in Figure 11, a chamfer can be provided at the edge of the substrate 12 as the second mark R2. Of course, other methods can also be used to set the second mark R2 in the substrate 12, which is not limited here.

[0094] Figure 12 is a schematic diagram of the structure of the second laser control system in this embodiment of the application. As shown in Figure 12, the second laser control system 30 may include: a third laser generator 301, a second reflected light receiver 302, a photoelectric signal converter 303, and a shaft controller 304. The third laser generator 301 emits a third laser T3, which passes through the second laser viewing window and is directed towards the surface of the tray 11. The second reflected light receiver 302 receives the second reflected light Y2 reflected from the surface of the tray 11 after the third laser T3 is directed towards it, and transmits the second reflected light Y2 to the photoelectric signal converter 303. The photoelectric signal converter 303 converts the received second reflected light Y2 into a reflected electrical signal and transmits the reflected electrical signal to the shaft controller 304. The shaft controller 304 controls the rotation of the first shaft 15 during the epitaxial growth process to drive the tray 11 to rotate, thereby ensuring a more uniform thickness of the formed epitaxial layer. Optionally, the shaft controller 304 can drive the first shaft 15 to rotate via a motor.

[0095] Furthermore, since the tray 11 rotates at a relatively high speed, in order for the first laser T1 to be directed toward the surface of the target substrate, the rotation axis controller 304 needs to control the tray 11 to slow down. The rotation axis controller 304 is also used to determine the time and period of the third laser T3 passing the first mark based on the reflected electrical signal, and, in conjunction with the positional relationship between the target substrate and the first mark, adjust the rotation speed of the first rotation axis 15 so that the rotation speed of the tray 11 is reduced to a first speed value, so that the first laser emitted by the first laser controller is directed toward the surface of the target substrate. Optionally, the first speed value can be zero or other values. Herein, the target substrate is the substrate for which a patterned epitaxial layer needs to be formed, and the positional relationship between the target substrate and the first mark can be the angular relationship between the target substrate and the first mark about the first rotation axis, or the positional relationship can be the distance between the target substrate and the first mark, or the positional relationship can be characterized by other parameters, which are not limited here.

[0096] As the third laser T3 passes through the first mark on the tray 11 during the rotation of the tray 11, and because the material and shape of the first mark in the tray 11 differ from those at other locations, the intensity of the second reflected light Y2 obtained by the third laser T3 when it is directed toward the first mark is different from the intensity of the second reflected light Y2 obtained by the third laser T3 when it is directed toward other locations outside the first mark. Therefore, the time and period of the third laser T3 passing through the first mark can be determined based on the second reflected light Y2.

[0097] Figure 13 shows the waveforms of the optical and electrical signals of the second reflected light acquired during the tray's rotation. As shown in Figure 13, with the signal corresponding to the first mark on the tray as 0 and the signals corresponding to positions other than the first mark on the tray as 1, the waveforms of the optical and electrical signals of the second reflected light are obtained. Furthermore, the waveforms of the electrical signals are consistent with those of the optical signals. The faster the tray rotates, the shorter the time it takes for the optical signal to be acquired in one rotation cycle. The duration of the first acquired cycle is t1. The rotation speed of the first shaft is adjusted to reduce the tray's rotation speed. The duration of the second acquired cycle is t2. The rotation speed of the first shaft is adjusted to reduce the tray's rotation speed. The duration of the third acquired cycle is t3. The rotation speed of the first shaft is adjusted to reduce the tray's rotation speed, and so on, until the nth cycle (n≥3), at which point the tray's speed smoothly decreases to the first speed value. Based on the patterns of the optical and electrical signals of the second reflected light shown in Figure 13, and combined with the positional relationship between the target substrate and the first mark (for example, the positional relationship can be the angle between the target substrate and the first mark about the first axis of rotation, or the positional relationship can be the distance between the target substrate and the first mark), the first laser emitted by the first laser controller can be controlled to accurately strike the surface of the target substrate, and the accuracy of controlling the first laser to strike the surface of the target substrate can be within 1 μm.

[0098] In practical implementation, when the tray rotates at the first speed value, the frequency of the first laser emitted by the first laser controller can be controlled so that the first laser is emitted when the first laser controller passes the position of the target substrate, and the first laser is not emitted when the first laser controller does not pass the position of the target substrate.

[0099] Furthermore, in embodiments of this application, the substrate carried by the carrier disk includes a second mark, and the photomask has alignment marks. As shown in FIG12, the spindle controller 304 is also used to adjust the rotation speed of the second spindle 112 to reduce the rotation speed of the carrier disk to a second speed value, so that the second mark at the target substrate is aligned with the alignment marks on the photomask. Optionally, the second speed value can be zero or other values. The spindle controller 304 can adjust the rotation speed of the second spindle 112 by airflow.

[0100] As shown in Figures 9 and 10, since the substrate 12 includes the second mark R2, Figures 9 and 10 illustrate the second mark R2 as a flat edge. During the rotation of the carrier disk 111, the path of the third laser T3 on the carrier disk 111 can pass through the surface of the carrier disk 111 and the surface of the substrate 12. Since the carrier disk 111 and the substrate 12 have different materials and shapes, the intensity of the second reflected light obtained by the third laser T3 when it is directed towards the carrier disk 111 and the substrate 12 is different. Therefore, the pattern of the third laser T3 passing through the carrier disk 111 and the substrate 12 can be determined based on the second reflected light.

[0101] Figure 14 shows the waveforms of the optical and electrical signals of the second reflected light acquired during the rotation of the carrier disk. As shown in Figure 14, with the signal corresponding to the substrate surface as 1 and the signal corresponding to the carrier disk surface as 0, the waveforms of the optical and electrical signals of the second reflected light are obtained. Furthermore, the waveforms of the electrical signals are consistent with those of the optical signals. The faster the carrier disk rotates, the shorter the duration of one rotation cycle of the optical signal acquisition substrate. The duration of the first acquired cycle is t1. The rotation speed of the second shaft is adjusted to reduce the rotation speed of the carrier disk. The duration of the second acquired cycle is t2. The rotation speed of the second shaft is adjusted to reduce the rotation speed of the carrier disk. The duration of the third acquired cycle is t3. The rotation speed of the second shaft is adjusted to reduce the rotation speed of the carrier disk, and so on until the nth cycle (n≥3), so that the rotation speed of the carrier disk smoothly decreases to the second speed value. Based on the pattern of the optical and electrical signals of the second reflected light shown in Figure 14, the alignment of the second mark on the target substrate with the alignment mark on the mask can be controlled, and the alignment accuracy can be controlled within 1μm.

[0102] In a specific implementation, as shown in Figure 12, the aforementioned second laser control system may further include: an optical lens 305, a second beam splitter 306, and a second condensing lens 307. The optical lens 305 is located on the light-emitting side of the third laser generator 301 and is used to transmit the third laser T3 emitted by the third laser generator 301 to the second beam splitter 306. The second beam splitter 306 is used to transmit the received third laser T3 to the second condensing lens 307, receive the second reflected light Y2 emitted by the second condensing lens 307, and transmit the second reflected light Y2 to the second reflected light receiver 302. The second condensing lens 307 is used to converge the third laser T3 and transmit the converged third laser T3 to the surface of the tray 11, receive the second reflected light Y2 reflected after the third laser T3 strikes the surface of the tray 11, and transmit the second reflected light Y2 to the second beam splitter 306. By setting the second beam splitter 306, the light emitted from the optical lens 305 can be transmitted to the second condenser lens 307, and the second reflected light Y2 emitted from the third condenser lens 307 can be transmitted to the second reflected light receiver 302. This simplifies the optical path of the second laser control system 30, makes the optical path of the second laser control system 30 more compact, and reduces the size of the second laser control system 30.

[0103] Figure 15 is a schematic diagram of another planar structure of the tray in an embodiment of this application. As shown in Figure 15, in some embodiments of this application, multiple carrier trays 111 can be arranged along at least two annular lines on the surface of the tray 11. Figure 15 illustrates an example of multiple carrier trays 111 arranged along three annular lines L1, L2, and L3, and assuming that the number of carrier trays 111 in each ring is the same. In specific implementations, multiple carrier trays 111 can also be arranged along two or more annular lines, and the number of carrier trays 111 in each ring can also be different. Combining Figures 1 and 15, the second laser viewing window U2 can be a strip-shaped structure extending radially along the tray 11. The position of the second laser viewing window U2 corresponds to at least two annular lines, and the length of the second laser viewing window U2 is greater than the width of at least two carrier trays. The second laser control system 30 can move along the extending direction of the second laser viewing window U2. In this way, by controlling the movement of the second laser control system 30, the third laser T3 emitted by the second laser control system 30 can be directed towards the substrate at different positions, facilitating the alignment of the substrate and the mask at different positions.

[0104] Based on the same technical concept, this application also provides a method for fabricating a semiconductor device. Figure 16 is a flowchart of the fabrication method provided in this application embodiment. As shown in Figure 16, the fabrication method may include:

[0105] S401. Referring to Figure 1, place the substrate 12 on the tray 11 in the epitaxial process reaction chamber 10 of any of the above-mentioned epitaxial devices;

[0106] S402. Referring to Figures 1 and 2, during the epitaxial growth process, the first laser control system 20 is controlled to emit a first laser T1. The first laser T1 passes through the first laser viewing window U1 and is directed towards the surface of the substrate 12 supported by the tray 11, thereby interfering with the epitaxial growth process. The area of ​​the substrate 12 not irradiated by the first laser T1 forms a first growth surface S1, and the area of ​​the substrate 12 irradiated by the first laser T1 forms a second growth surface S2. The surface morphology of the second growth surface S2 is different from that of the first growth surface S1.

[0107] S403. As shown in Figure 3, the epitaxial layer formed by the epitaxial growth process is subjected to high-temperature annealing to cause the epitaxial layer formed on the second growth surface to fall off, thereby obtaining a patterned epitaxial layer. For example, the structure shown in Figure 4 can be obtained.

[0108] In the fabrication method provided in this application embodiment, during the epitaxial growth process, a first laser control system emits a first laser. The first laser can interfere with the epitaxial growth process, changing the surface morphology of the substrate. The area of ​​the substrate surface irradiated by the first laser forms a second growth surface, while the area of ​​the substrate surface not irradiated by the first laser forms a first growth surface. Because the surface morphology of the second growth surface differs from that of the first growth surface, the crystal quality of the epitaxial layer formed at the second growth surface is poor, causing the epitaxial layer formed at the second growth surface to detach after annealing, thus obtaining a patterned epitaxial layer. Therefore, in this application embodiment, a patterned epitaxial layer can be formed within the epitaxial process reaction chamber, eliminating the need to remove the substrate from the epitaxial process reaction chamber and then perform the patterning process using other equipment. This avoids the chemical substances in dry etching or wet etching processes affecting the step interfaces of the epitaxial layer, effectively protecting the steps of the epitaxial layer and improving the electrical reliability of the semiconductor device.

[0109] In specific implementation, step S402 above, during the epitaxial growth process, controlling the first laser control system to emit the first laser may include:

[0110] During the epitaxial growth process, the first laser generator in the first laser control system emits a first laser and the second laser generator emits a second laser.

[0111] The laser modulator in the first laser control system adjusts the power and frequency of the first and second lasers;

[0112] The first reflected light receiver in the first laser control system receives the first reflected light reflected from the surface of the substrate, processes the first reflected light to obtain a reflected signal corresponding to the second laser, and feeds the obtained reflected signal back to the laser modulator.

[0113] The laser modulator determines the surface roughness of the second growth surface based on the reflected signal, and readjusts the power and frequency of the first laser based on the determined surface roughness until the surface roughness of the second growth surface reaches the set threshold.

[0114] In this embodiment, the first laser generator in the first laser control system emits a first laser and the second laser generator emits a second laser. By acquiring the first reflected light obtained after the second laser is directed onto the substrate surface, the surface roughness of the second growth surface is reflected according to the principle of light interference. Then, the power and frequency of the first laser are adjusted according to the obtained surface roughness so that the roughness of the second growth surface reaches the set value, thereby improving the patterning effect of the epitaxial layer.

[0115] In practical applications, in some embodiments of this application, the above-described manufacturing method may further include:

[0116] The third laser generator in the second laser control system emits a third laser, which passes through the second laser viewing window and is directed onto the surface of the tray.

[0117] The photoelectric signal converter in the second laser control system converts the second reflected light received from the surface of the tray into a reflected electrical signal, and transmits the reflected electrical signal to the shaft controller.

[0118] The control shaft controller controls the rotation of the first shaft to drive the tray to rotate;

[0119] The control axis controller determines the time and period of the third laser passing through the first mark on the tray based on the reflected electrical signal, and adjusts the rotation speed of the first axis in combination with the positional relationship between the target substrate and the first mark, so that the rotation speed of the tray is reduced to the first speed value, so that the first laser emitted by the first laser controller is directed toward the surface of the target substrate, wherein the target substrate is the substrate for which a patterned epitaxial layer needs to be formed.

[0120] During the tray rotation, the path of the third laser on the tray passes through the first mark. Due to differences in material and shape between the first mark and other locations on the tray, the intensity of the second reflected light obtained when the third laser strikes the first mark differs from the intensity of the second reflected light obtained when the third laser strikes other locations outside the first mark. Therefore, the timing and pattern of the third laser passing through the first mark can be determined based on the second reflected light. The patterns of the optical and electrical signals of the second reflected light, combined with the positional relationship between the target substrate and the first mark, control the first laser emitted by the first laser controller to be directed towards the surface of the target substrate, thus ensuring that the first laser accurately strikes the surface of the target substrate.

[0121] Furthermore, the manufacturing method provided in the embodiments of this application may also include:

[0122] The control spindle controller adjusts the rotation speed of the second spindle to reduce the rotation speed of the carrier disk to a second speed value so that the second mark on the target substrate is aligned with the alignment mark on the mask.

[0123] During the rotation of the carrier disk, the path of the third laser on the carrier disk can pass through the surface of the carrier disk and the surface of the substrate. Due to the differences in materials and shapes between the carrier disk and the substrate, the intensity of the second reflected light obtained by the third laser when it is directed at the carrier disk and the substrate is different. Therefore, the pattern of the third laser passing through the carrier disk and the substrate can be determined based on the second reflected light. Thus, the alignment of the second mark on the target substrate with the alignment mark on the mask can be controlled.

[0124] The implementation of the manufacturing method provided in this application embodiment can refer to the implementation of any of the above-described epitaxial devices, and the repeated parts will not be described in detail.

[0125] Thirdly, embodiments of this application also provide a semiconductor device that can be fabricated using any of the aforementioned epitaxial equipment. Because the epitaxial equipment provided in this application allows for the formation of a patterned epitaxial layer within the epitaxial process reaction chamber, eliminating the need to remove the substrate from the reaction chamber and then perform patterning using other equipment, the chemical substances in dry or wet etching processes can be avoided from affecting the step interfaces of the epitaxial layer. This effectively protects the steps of the epitaxial layer, resulting in high electrical reliability of the semiconductor device provided in this application.

[0126] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0127] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. An epitaxial device, characterized in that, include: An epitaxial process reaction chamber and a first laser control system are provided; the epitaxial process reaction chamber is provided with a tray for supporting at least one substrate, and the epitaxial process reaction chamber includes a first laser viewing window; the first laser control system is used to emit a first laser, and after the first laser viewing window passes through the first laser viewing window, it is directed towards the surface of the substrate supported by the tray; the first laser is used to interfere with the epitaxial growth process; during the epitaxial growth process, the area of ​​the substrate surface not irradiated by the first laser forms a first growth surface, and the area of ​​the substrate surface irradiated by the first laser forms a second growth surface; the surface morphology of the second growth surface is different from that of the first growth surface; the first growth surface is used to grow a first epitaxial layer, and the second growth surface is used to grow a second epitaxial layer.

2. The epitaxial device as described in claim 1, characterized in that, The first laser control system includes: a first laser generator and a mask; the mask includes a light-transmitting area and a light-blocking area; the first laser generator is used to emit the first laser and direct the first laser toward the mask, so that the first laser passes through the light-transmitting area of ​​the mask and is directed toward the surface of the substrate carried by the tray.

3. The epitaxial device as described in claim 2, characterized in that, The first laser control system further includes: a second laser generator, a laser modulator, and a first reflected light receiver; the second laser generator is used to emit a second laser, the wavelength of which is greater than the wavelength of the first laser; the laser modulator is used to receive the first laser emitted by the first laser generator and the second laser emitted by the second laser generator, and direct the modulated first laser and second laser toward the photomask so that the first laser and second laser pass through the light-transmitting area of ​​the photomask and then are directed toward the surface of the substrate carried by the tray; the first reflected light receiver is used to receive the first reflected light reflected from the surface of the substrate, process the first reflected light to obtain a reflection signal corresponding to the second laser, and feed the obtained reflection signal back to the laser modulator.

4. The epitaxial device as described in claim 3, characterized in that, The first laser control system further includes: a first focusing lens and a first beam splitter; the first focusing lens is located on the light-emitting side of the laser modulator and is used to converge the first laser and the second laser emitted from the laser modulator, and to direct the converged first laser and the second laser toward the first beam splitter; the first beam splitter is used to transmit the first laser and the second laser converged by the first focusing lens to the mask, and to reflect the first reflected light reflected from the surface of the substrate to the first reflected light receiver.

5. The epitaxial device as described in claim 3, characterized in that, The wavelength of the first laser is less than 365nm, and the wavelength of the second laser is greater than 365nm.

6. The epitaxial device according to any one of claims 2 to 5, characterized in that, It also includes: a first rotating shaft connected to the tray; the first rotating shaft is used to drive the tray to rotate; the surface of the tray is provided with a plurality of support plates, the support plates are used to support the substrate; the plurality of support plates are arranged on the surface of the tray along at least one annular line, the annular line being symmetrical about the first rotating shaft as a central axis; the support plates are connected to the tray through a second rotating shaft, the second rotating shaft being used to drive the support plates to rotate.

7. The epitaxial device as described in claim 6, characterized in that, Also includes: The second laser control system; the epitaxial process reaction cavity further includes a second laser viewing window; the second laser control system is used to emit a third laser, and after the third laser passes through the second laser viewing window, it is directed toward the surface of the tray; the surface of the tray is provided with a first mark; during the rotation of the tray, the path of the third laser on the tray passes through the first mark.

8. The epitaxial device as described in claim 7, characterized in that, The second laser control system includes: a third laser generator, a second reflected light receiver, a photoelectric signal converter, and a rotation axis controller; the third laser generator emits a third laser beam, which passes through the second laser viewing window and is directed towards the surface of the tray; the second reflected light receiver receives the second reflected light reflected from the surface of the tray after the third laser beam hits it, and transmits the second reflected light to the photoelectric signal converter; the photoelectric signal converter converts the received second reflected light into a reflected electrical signal and transmits the reflected electrical signal to the rotation axis controller; the rotation axis controller controls the rotation of the first rotation axis during the epitaxial growth process to drive the tray to rotate.

9. The epitaxial device as described in claim 8, characterized in that, The substrate carried by the carrier disk also includes a second mark; the mask is provided with an alignment mark; the rotation controller is also used to adjust the rotation speed of the second rotation shaft so that the rotation speed of the carrier disk is reduced to a second speed value so that the second mark at the target substrate is aligned with the alignment mark on the mask.

10. The epitaxial device as described in claim 8, characterized in that, The second laser control system further includes: an optical lens, a second beam splitter, and a second condenser lens; the optical lens is located on the light-emitting side of the third laser generator and is used to transmit the third laser emitted by the third laser generator to the second beam splitter; the second beam splitter is used to transmit the received third laser to the second condenser lens, receive the second reflected light emitted by the second condenser lens, and transmit the second reflected light to the second reflected light receiver; the second condenser lens is used to converge the third laser and transmit the converged third laser to the surface of the tray, receive the second reflected light reflected after the third laser is incident on the surface of the tray, and transmit the second reflected light to the second beam splitter.

11. The epitaxial device as claimed in claim 8, characterized in that, The plurality of carrier plates are arranged on the surface of the tray along at least two of the annular lines; the second laser viewing window is a strip-shaped structure extending radially along the tray; the position of the second laser viewing window corresponds to at least two of the annular lines, and the length of the second laser viewing window is greater than the width of at least two of the carrier plates; the second laser control system moves along the extending direction of the second laser viewing window.

12. The epitaxial device according to any one of claims 1 to 5, characterized in that, The epitaxial process reaction chamber is also equipped with a heater; the heater is located on the side of the tray opposite to the first laser viewing window.

13. A semiconductor device, characterized in that, The semiconductor device is fabricated using the epitaxial equipment as described in any one of claims 1 to 12.

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