Method for realizing gallium nitride semi-insulating substrate through proton irradiation

Abstract

The invention belongs to the technical field of semiconductors, and provides a method for realizing a gallium nitride semi-insulating substrate by proton irradiation, which comprises the following steps of: preparing an unintentionally doped gallium nitride single crystal substrate; performing proton irradiation treatment on the gallium nitride single crystal substrate by using a proton irradiation device; and after the irradiation is completed, cutting the processed gallium nitride wafer into a plurality of thin sheets. After proton irradiation, Ga atoms and N atoms in GaN can absorb energy of H ions and move from original lattice positions to form N vacancies, Ga vacancies and anti-position defects of N, Ga vacancies and N, the defects can play a role of a carrier recombination center, the effect of reducing the carrier concentration is achieved by adsorbing carriers, and then the resistivity of the material is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for realizing a gallium nitride semi-insulating substrate by proton irradiation. Background Art

[0002] Gallium nitride (GaN), as a third-generation semiconductor material, has the advantages of wide bandgap, high breakdown electric field, and high saturation electron velocity. It has broad application prospects in high-frequency, high-power electronic devices and optoelectronic devices. However, in practical applications, due to the quality and characteristics of the substrate material itself (such as conductivity), GaN materials are prone to introduce unnecessary parasitic effects or leakage currents in certain scenarios, affecting device performance. Therefore, the development of high-quality, semi-insulating gallium nitride substrates has become the key to improving device performance. Semi-insulating substrates are particularly important in scenarios such as high-frequency devices and radio frequency devices (such as microwave communications and 5G applications). They can effectively reduce the leakage current and parasitic effects introduced by the substrate and improve the high-frequency performance and efficiency of the device.

[0003] At present, the following methods are mainly used to realize GaN semi-insulating substrate materials: (1) doping with elements such as Fe to suppress carrier concentration. Although it can increase the resistivity of the material, the impurity distribution is often uneven, resulting in inconsistent electrical properties in local areas and poor thermal stability; (2) using silicon carbide (SiC) and sapphire as heterogeneous substrates, but there are problems such as low thermal conductivity and large lattice mismatch, which affect the quality of the substrate and device performance. Summary of the invention

[0004] Based on these problems, the purpose of the present invention is to provide a method for realizing a semi-insulating substrate of gallium nitride by proton irradiation, which introduces defects into gallium nitride crystals by high-energy proton irradiation. These defects can act as carrier traps, capturing free electrons or holes, thereby reducing the carrier concentration of the material, increasing the resistivity of the material, and gradually causing gallium nitride to move from its original conductive state to a semi-insulating state.

[0005] To achieve the above object, the present invention provides the following technical solutions.

[0006] In a first aspect, the present invention provides a method for realizing a gallium nitride semi-insulating substrate by proton irradiation, comprising the following steps:

[0007] preparing a non-intentionally doped gallium nitride single crystal substrate;

[0008] Performing proton irradiation treatment on the gallium nitride single crystal substrate using a proton irradiation device;

[0009] After irradiation, the processed GaN wafer is cut into several thin slices.

[0010] As a further solution of the present invention, the prepared gallium nitride single crystal substrate has a thickness of 200-1000 microns, preferably 500 microns.

[0011] As a further embodiment of the present invention, the specific steps of proton irradiation treatment include:

[0012] a) Target chamber setting: A mobile irradiation target stand is arranged in the target chamber. The target stand is driven by a bottom motor and moves along the Y-axis and Z-axis directions, and can rotate around the Z-axis at a certain angle;

[0013] b) Sample installation and positioning: A rectangular porous resin plate for mounting the device to be irradiated is fixed on the target frame. The device to be irradiated is pre-positioned by a cross laser on the inner wall of the target chamber, and the positioning coordinates of the device are recorded;

[0014] c) Vacuum system and beam diagnosis: hoist the top cover to seal the target chamber, turn on the vacuum system, and perform beam diagnosis after the set air pressure is reached;

[0015] d) Accelerator preparation: using an accelerator to draw an ion beam from an ion source;

[0016] e) Beam guidance and adjustment: The ion beam is drawn out from the ion source, accelerated and transmitted to the branch pipe, deflected by the quadrupole magnet, collimated by the guide, and evenly diffused on the scattering target, and then the beam spot size is adjusted by the slit light barrier;

[0017] f) Preparation for irradiation experiment: After ensuring that the beam diagnosis is correct, start the irradiation experiment.

[0018] As a further solution of the present invention, a rectangular porous resin plate of 50x50 cm is fixed on the target frame.

[0019] As a further solution of the present invention, beam diagnosis is performed by a detector array fixed on the target holder to measure the beam energy and flux. During the irradiation process, the pressure in the vacuum target chamber is kept constant at 4x10 -3 Pa.

[0020] As a further embodiment of the present invention, the accelerator is an HI-13 tandem accelerator. 1 H- 197 The ion beam current between Au.

[0021] As a further solution of the present invention, when the irradiation experiment starts, multiple devices are placed on the target frame, and the movement of the target frame is remotely controlled according to the recorded positioning coordinates to switch the devices.

[0022] As a further solution of the present invention, the proton irradiation treatment is carried out at room temperature, a large beam spot of 5x5 cm is selected, and the beam uniformity is better than 90%.

[0023] As a further embodiment of the present invention, the irradiation treatment conditions are as follows: the injection energy is 50 MeV, the dose is 1×10 17 cm -2 .

[0024] As a further solution of the present invention, the gallium nitride wafer is cut into a plurality of slices with a thickness of 100 microns.

[0025] Compared with the prior art, the method for realizing a gallium nitride semi-insulating substrate by proton irradiation provided by the present invention can effectively improve the resistivity of the gallium nitride substrate and achieve a semi-insulating effect, and has the following beneficial effects:

[0026] 1. Improved resistivity. The present invention can introduce a large number of defects in the gallium nitride substrate through proton irradiation treatment, such as N vacancies, Ga vacancies and N anti-site defects. These defects act as carrier recombination centers and adsorb free carriers, thereby significantly reducing the carrier concentration of the material and ultimately improving the resistivity. The method of the present invention can increase the resistivity of the gallium nitride material to a semi-insulating level, and is suitable for the manufacture of high-frequency electronic devices and optoelectronic devices.

[0027] 2. Achieved uniform irradiation. The present invention uses the proton beam provided by the China Advanced Research Reactor (CARR) and the HI-13 tandem accelerator, combined with the target frame movement and rotation system, to achieve uniform irradiation of a large area. The beam uniformity is better than 90%, ensuring the electrical performance consistency of the gallium nitride substrate in the entire irradiation area, thereby improving the reliability of the material and the performance of the device.

[0028] 3. The irradiation parameters are precisely controlled. The present invention sets the proton injection energy to 50 MeV and the dose to 1×10 17 cm -2 , which can accurately control the defect concentration and distribution introduced during the irradiation process, combined with the cross laser pre-positioning in the target chamber and the beam diagnosis of the detector array to ensure the accuracy and repeatability of the irradiation process.

[0029] 4. Efficient experimental process. The present invention reduces the need for frequent destruction of the vacuum system during the experiment and improves the experimental efficiency by adopting the method of automatic movement of the target frame and placement of multiple devices. At the same time, the movement of the target frame is remotely controlled to achieve continuous irradiation treatment of multiple devices, thereby improving the degree of automation and production efficiency of the experiment. After the irradiation is completed, the gallium nitride wafer is cut into several thin slices with a thickness of 100 microns. Thin slices of this thickness are suitable for subsequent device processing and packaging processes. The cut slices still maintain a high resistivity and are suitable for substrate materials for various microelectronic and optoelectronic devices.

[0030] 5. Wide range of applications. The semi-insulating gallium nitride substrate prepared by the present invention has high resistivity and excellent thermal stability, and is suitable for manufacturing high-frequency, high-power electronic devices, such as high electron mobility transistors (HEMTs), microwave monolithic integrated circuits (MMICs), etc. At the same time, it can also be used in optoelectronic devices such as laser diodes, light-emitting diodes, etc., and has a wide range of application prospects.

[0031] In summary, the present invention provides an efficient, precise and uniform method for realizing a gallium nitride semi-insulating substrate by proton irradiation, which can significantly improve the resistivity of the gallium nitride substrate, meet the requirements of semi-insulating materials, and provide reliable technical support for the manufacture of high-performance electronic and optoelectronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention.

[0033] Figure 1 A process flow chart of a method for realizing a gallium nitride semi-insulating substrate by proton irradiation provided by the present invention;

[0034] Figure 2 A schematic diagram of the irradiation principle of a gallium nitride semi-insulating substrate in a method for realizing a gallium nitride semi-insulating substrate by proton irradiation provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following description and the accompanying drawings fully illustrate the specific embodiments of this paper so that those skilled in the art can practice them. The parts and features of some embodiments may be included in or replace the parts and features of other embodiments. The scope of the embodiments herein includes the entire scope of the claims, and all available equivalents of the claims.

[0036] Herein, the terms "first", "second", etc. are used only to distinguish one element from another, without requiring or implying any actual relationship or order between these elements. In fact, the first element can also be called the second element, and vice versa. Moreover, the terms "comprise", "comprising", or any other variants thereof are intended to cover non-exclusive inclusion, so that a structure, system, or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such structure, system, or device.

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[0038] Since the existing method suppresses the carrier concentration by doping elements such as iron (Fe) when preparing a semi-insulating substrate of gallium nitride (GaN), although the resistivity of the material can be improved, the impurity distribution is often uneven, resulting in inconsistent electrical properties in local areas and poor thermal stability; when silicon carbide (SiC) or sapphire is used as a heterogeneous substrate, although it helps to form a semi-insulating structure, such materials have problems of low thermal conductivity and large lattice mismatch, which affects the quality of the substrate and device performance. Based on this, the present invention provides a method for realizing a semi-insulating substrate of gallium nitride by proton irradiation, which introduces defects in gallium nitride crystals by high-energy proton irradiation. These defects can act as carrier traps, capture free electrons or holes, thereby reducing the carrier concentration of the material, increasing the resistivity of the material, and causing gallium nitride to gradually tend from its original conductive state to a semi-insulating state.

[0039] The technical solution of the present invention is further described below in conjunction with specific embodiments:

[0040] See also Figure 1 As shown, an embodiment of the present invention provides a method for realizing a gallium nitride semi-insulating substrate by proton irradiation, comprising the following steps:

[0041] Step S10: prepare a non-intentionally doped gallium nitride single crystal substrate with a thickness of 500 μm (range 200-1000 μm).

[0042] Step S20: Use the China Advanced Research Reactor (CARR) of the China Institute of Atomic Energy, also known as the "Yanlong" pool reactor, to perform proton irradiation treatment on the unintentionally doped substrate. The specific irradiation process is as follows:

[0043] a) Target chamber setting: A mobile irradiation target stand is set in the target chamber. The target stand is driven by a bottom motor and can move along the Y-axis and Z-axis directions and can rotate around the Z-axis at a certain angle.

[0044] b) Sample installation and positioning: A 50x50cm rectangular porous resin plate is fixed on the target frame for mounting the device to be irradiated. The device to be irradiated is pre-positioned by the cross laser on the inner wall of the target chamber, and the positioning coordinates of the device are recorded.

[0045] c) Vacuum system and beam diagnosis: The top cover is hoisted to close the target chamber, and the vacuum system is turned on. Beam diagnosis is performed after the set air pressure is reached. Beam diagnosis is completed by the detector array fixed on the target holder to measure the beam energy and flux. During the irradiation process, the air pressure in the vacuum target chamber is kept constant at 4x10 -3 Pa.

[0046] d) Accelerator preparation: Use the HI-13 tandem accelerator, which is a domestic advanced nuclear physics comprehensive research platform. The accelerator can produce 1 H- 197 Most of the ion beam current is between Au.

[0047] e) Beam guidance and adjustment: The beam is drawn out from the ion source, accelerated and transmitted to the branch pipe. The direction is deflected by the quadrupole magnet, and then the beam is collimated by the guide. The beam is evenly diffused on the scattering target, and then the beam spot size is adjusted by the slit light barrier.

[0048] f) Preparation for irradiation experiment: After ensuring that the beam diagnosis is correct, the irradiation experiment begins. To avoid frequent damage to the vacuum system, multiple devices are placed on the target frame, and the target frame is remotely controlled to move according to the recorded positioning coordinates to achieve device switching.

[0049] g) Proton irradiation parameters: Proton irradiation was carried out at room temperature, with a large beam spot of 5x5 cm and a beam uniformity better than 90%. The irradiation treatment conditions were injection energy of 50 MeV and a dose of 1×10 17 cm -2 .

[0050] Step S30: cutting the processed GaN wafer into a plurality of slices with a thickness of 100 microns.

[0051] See also Figure 2 As shown, the embodiment of the present invention adopts a method for realizing a gallium nitride semi-insulating substrate by proton irradiation. After proton irradiation, Ga atoms and N atoms in GaN absorb the energy of H ions and move from their original lattice positions to form N vacancies, Ga vacancies and N antisite defects. Such defects act as carrier recombination centers, and reduce the carrier concentration by adsorbing carriers, thereby increasing the resistivity of the material.

[0052] The present invention proposes a method for realizing a semi-insulating substrate of gallium nitride by proton irradiation, the typical feature of which is that high-energy proton irradiation will introduce defects into the gallium nitride crystal. These defects can act as carrier traps, capturing free electrons or holes, thereby reducing the carrier concentration of the material, increasing the resistivity of the material, and causing gallium nitride to gradually move from its original conductive state to a semi-insulating state.

[0053] The method of realizing a gallium nitride semi-insulating substrate by proton irradiation in the present invention can achieve:

[0054] (1) Precise control: By adjusting the parameters of irradiation energy, dose, and irradiation time, the introduction of defects and changes in electrical properties in GaN materials can be precisely controlled to achieve the desired semi-insulating properties.

[0055] (2) Non-contact processing: Proton irradiation is a non-contact processing method that does not cause mechanical damage to the material surface and is beneficial to maintaining the crystal quality and surface flatness of the material.

[0056] (3) Low cost and high efficiency: Compared with the traditional preparation method, the proton irradiation equipment used in the present invention is relatively simple and low cost, and the processing process can be completed in a shorter time, thereby improving production efficiency.

[0057] Therefore, the method of realizing a semi-insulating gallium nitride substrate by proton irradiation in the present invention is typically characterized in that defects are introduced into the gallium nitride crystal by high-energy proton irradiation. These defects can act as carrier traps, capturing free electrons or holes, thereby reducing the carrier concentration of the material, increasing the resistivity of the material, and causing gallium nitride to gradually tend from its original conductive state to a semi-insulating state. Compared with traditional methods for realizing a semi-insulating gallium nitride substrate, proton irradiation has the advantages of precise control, non-contact processing, low cost, and high efficiency. Any semi-insulating gallium nitride substrate or device based on similar proton irradiation is protected.

[0058] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for realizing a gallium nitride semi-insulating substrate by proton irradiation, characterized in that: The following steps are involved: preparing a non-intentionally doped gallium nitride single crystal substrate; Performing proton irradiation treatment on the gallium nitride single crystal substrate using a proton irradiation device; After irradiation, the processed GaN wafer is cut into several thin slices.

2. The method for realizing gallium nitride semi-insulating substrate by proton irradiation according to claim 1, characterized in that: The thickness of the prepared gallium nitride single crystal substrate is 200-1000 microns.

3. The method for realizing gallium nitride semi-insulating substrate by proton irradiation according to claim 2, characterized in that: The thickness of the prepared gallium nitride single crystal substrate is 500 microns.

4. The method for realizing gallium nitride semi-insulating substrate by proton irradiation according to claim 1, characterized in that: The specific steps of proton irradiation treatment include: a) Target chamber setting: A mobile irradiation target stand is arranged in the target chamber. The target stand is driven by a bottom motor and moves along the Y-axis and Z-axis directions, and can rotate around the Z-axis at a certain angle; b) Sample installation and positioning: A rectangular porous resin plate for mounting the device to be irradiated is fixed on the target frame. The device to be irradiated is pre-positioned by a cross laser on the inner wall of the target chamber, and the positioning coordinates of the device are recorded; c) Vacuum system and beam diagnosis: hoist the top cover to seal the target chamber, turn on the vacuum system, and perform beam diagnosis after the set air pressure is reached; d) Accelerator preparation: using an accelerator to draw an ion beam from an ion source; e) Beam guidance and adjustment: The ion beam is drawn out from the ion source, accelerated and transmitted to the branch pipe, deflected by the quadrupole magnet, collimated by the guide, and evenly diffused on the scattering target, and then the beam spot size is adjusted by the slit light barrier; f) Preparation for irradiation experiment: After ensuring that the beam diagnosis is correct, start the irradiation experiment.

5. The method for realizing gallium nitride semi-insulating substrate by proton irradiation according to claim 4, characterized in that: A 50x50cm rectangular porous resin plate is fixed on the target stand.

6. The method for realizing gallium nitride semi-insulating substrate by proton irradiation according to claim 4, characterized in that: Beam diagnosis is performed by a detector array fixed on the target holder to measure the beam energy and flux. During the irradiation process, the pressure in the vacuum target chamber is kept constant at 4x10 -3 Pa.

7. The method for realizing gallium nitride semi-insulating substrate by proton irradiation according to claim 4, characterized in that: The accelerator is a HI-13 tandem accelerator. 1 H- 197 The ion beam current between Au.

8. The method for realizing gallium nitride semi-insulating substrate by proton irradiation according to claim 4, characterized in that: When the irradiation experiment begins, multiple devices are placed on the target stand, and the movement of the target stand is remotely controlled according to the recorded positioning coordinates to switch the devices.

9. The method for realizing gallium nitride semi-insulating substrate by proton irradiation according to claim 8, characterized in that: The proton irradiation treatment was carried out at room temperature, a large beam spot of 5x5 cm was selected, and the beam uniformity was better than 90%.

10. The method for realizing gallium nitride semi-insulating substrate by proton irradiation according to claim 9, characterized in that: The irradiation treatment conditions were as follows: the injection energy was 50 MeV and the dose was 1×10 17 cm -2 .

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