Method for optimizing ohmic contact structure on back surface of GaN device through sin insertion layer
By forming a concave and convex structure on the surface of the sin layer of the GaN device and forming a physical interlock with the metal contact layer, the problems of high contact resistance, insufficient thermal stability and poor interface status of traditional GaN devices are solved, and the conduction performance of the device is significantly improved. Thermal management and electrical performance.
Patent Information
- Application Number
- CN202420974099.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-08
- Publication Date
- 2025-02-14
- Estimated Expiration
- 2034-05-08
AI Technical Summary
The ohmic contact structure of the sin insertion layer in traditional GaN devices has problems such as high contact resistance, insufficient thermal stability and poor interface state, which affects the device's conductivity, thermal management and electrical performance.
By forming an uneven structure on the surface of the sin layer and forming a physical interlock with the metal contact layer, the mechanical bonding force of the interface is enhanced, the contact layer stripping phenomenon is reduced, and the heat flow channel and carrier transmission characteristics are improved.
Significantly reduce contact resistance, improve the device's conductivity and power efficiency; improve thermal management, improve the device's thermal stability and long-term reliability; optimize interface quality, improve the device's high-frequency performance and overall electrical performance .
Smart Images
Figure CN222485186U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of GaN devices, and in particular relates to an ohmic contact structure on the back side of a GaN device optimized by a sin insertion layer. Background Art
[0002] Gallium nitride (GaN) devices have been widely used in high-performance electronics and optoelectronics in recent years due to their excellent physical properties, such as wide bandgap, high breakdown electric field, and high saturation electron mobility. In particular, GaN devices have shown unparalleled advantages in high-power electronic devices, radio frequency devices, and solid-state lighting. GaN devices are mainly divided into two categories: high electron mobility transistors (HEMTs) based on heterojunctions and metal-semiconductor field-effect transistors (MESFETs). The core of these devices lies in their wide energy gap, high temperature resistance, and excellent high-frequency performance, making them key components of next-generation power conversion and wireless communication systems. In the structural design of GaN devices, ohmic contact is the key link to achieve low-resistance connection of devices, which directly affects the on-resistance, thermal performance, and overall efficiency of the devices. Traditional ohmic contact structures usually rely on direct contact between metals and semiconductors, but due to the work function mismatch between GaN and most metals, as well as the natural oxide layer on the surface of GaN, the contact resistance is high, which affects the device performance. In order to solve this problem, the introduction of sin (usually refers to silicon nitride, SiN_x) insertion layer has become a common strategy. As a dielectric layer, the sin layer not only provides good insulation properties, but also, through appropriate doping and process treatment, can serve as an intermediate layer for ohmic contact to improve the contact performance between metal and GaN.
[0003] However, the ohmic contact structure of the sin insertion layer in traditional GaN devices still has some drawbacks: Contact resistance problem: Although the sin layer can improve the contact, the control of its thickness and quality is extremely strict. Any inappropriateness will lead to increased contact resistance, affecting the conduction performance and efficiency of the device. Insufficient thermal stability: Under high-power operation, GaN devices will generate a lot of heat energy. As a medium, the traditional sin layer has a relatively low thermal conductivity and may become a thermal bottleneck, leading to the formation of local hot spots, affecting the thermal management and reliability of the device. Interface state: There may be a large number of dangling bonds or defects at the interface between the sin layer and the GaN substrate. These interface states will become traps or scattering centers for carriers, affecting the electrical properties of the device, especially the high-frequency performance. Utility Model Content
[0004] In view of this, the utility model provides an ohmic contact structure on the back side of a GaN device optimized by a sin insertion layer, and forms a physical interlock through a concave-convex structure, thereby solving the contact layer peeling phenomenon of traditional GaN devices under high temperature or high pressure conditions and improving the reliability of GaN devices.
[0005] The utility model is achieved in this way:
[0006] The utility model provides an ohmic contact structure on the back side of a GaN device optimized by a sin insertion layer, comprising a GaN substrate and a sin layer disposed on the back side of the GaN substrate, wherein the sin layer is provided with a concave-convex structure, the concave-convex structure is specifically a protrusion formed on the surface of the sin layer, the GaN substrate is further provided with a metal contact layer, the metal contact layer is in contact with the concave-convex structure, the metal contact layer is provided with a structure matching the protrusion on the surface of the sin layer, and the sin layer and the metal contact layer are physically interlocked through the concave-convex structure;
[0007] Wherein, the concave-convex structure is periodically distributed on the surface of the sin layer.
[0008] The utility model provides a technical effect of optimizing the ohmic contact structure on the back side of a GaN device through a sin insertion layer, which is as follows: through the physical interlocking structure of the sin layer and the metal contact layer, the mechanical bonding force of the interface is significantly enhanced, the contact layer peeling phenomenon under high temperature or high pressure conditions is effectively reduced, and the long-term reliability of the device is improved.
[0009] On the basis of the above technical solution, the utility model can also make the following improvements to optimize the back ohmic contact structure of GaN device by inserting a sin layer:
[0010] Wherein, the depth of the concave-convex structure ranges from 20nm to 100nm, and the width ranges from 80nm to 400nm.
[0011] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the size of the fine concave-convex structure optimizes the contact area, reduces the contact resistance, and at the same time maintains the stability of the structure and improves the conductivity.
[0012] Furthermore, the cross-sectional shape of the concave-convex structure is columnar, conical, pyramidal or corrugated.
[0013] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: concave-convex structures of different shapes can adapt to different application requirements. For example, the conical structure can better adapt to thermal expansion differences and reduce interface stress.
[0014] Furthermore, the concave-convex structures are arranged in a regular hexagon, rectangle or triangle, and the arrangement spacing is equal to 1 to 3 times the width range of the concave-convex structures.
[0015] The beneficial effects of adopting the above-mentioned improvement scheme are: the orderly arranged concave-convex structure optimizes the heat flow and charge transfer path, and improves the working efficiency of the device.
[0016] Furthermore, the thickness of the metal contact layer is 100 nm to 300 nm.
[0017] Furthermore, the thickness of the sin layer ranges from 20 nm to 80 nm.
[0018] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the specific thickness range of the sin layer ensures good electrical insulation performance, while allowing effective carrier tunneling, thereby optimizing the electrical performance of the device.
[0019] Furthermore, the contact area between the metal contact layer and the sin layer is increased to 1.2 to 3 times of the original planar contact area through the concave-convex structure.
[0020] The original plane contact area is specifically the direct contact area between the metal contact layer and the sin layer.
[0021] Furthermore, the concave-convex structure is formed by nano-imprinting, electron beam lithography or laser interference lithography technology.
[0022] Furthermore, the ratio of the depth to the width of the concave-convex structure is 0.5 to 2.
[0023] Furthermore, the metal contact layer is made of titanium, aluminum, nickel, gold or an alloy thereof.
[0024] Compared with the prior art, the utility model provides a method for optimizing the back ohmic contact structure of a GaN device by inserting a sin layer, which has the following beneficial effects:
[0025] Significantly reduce contact resistance: By forming a fine protrusion structure on the surface of the sin layer and forming a tight physical interlock with the metal contact layer, the actual contact area is greatly increased, the contact resistance is effectively reduced, and the conductivity and power efficiency of the device are improved;
[0026] Improved thermal management: The special design of the interlocking structure enhances the heat flow channel, which helps to quickly conduct heat energy from the GaN layer to the metal layer and then to the external heat sink, effectively alleviating local thermal effects and improving the thermal stability and long-term working reliability of the device;
[0027] Optimize interface quality: By precisely controlling the growth and processing of the sin layer, the interface state density is reduced, carrier scattering is reduced, and the high-frequency performance and overall electrical performance of the device are improved;
[0028] Enhanced mechanical stability: The physical interlocking structure increases the mechanical bite force of the contact interface, making the contact layer less likely to fall off when the device undergoes thermal cycling and mechanical stress, significantly improving the mechanical stability and life of the device. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments of the utility model will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0030] Figure 1 This is an example diagram of a first embodiment of an ohmic contact structure on the back side of a GaN device optimized by inserting a sin layer;
[0031] Figure 2 This is an example diagram of a second embodiment of an ohmic contact structure on the back side of a GaN device optimized by inserting a sin layer;
[0032] In the accompanying drawings, the components represented by the reference numerals are listed as follows:
[0033] 10. GaN substrate; 20. sin layer; 30. concave-convex structure; 40. metal contact layer. DETAILED DESCRIPTION
[0034] In order to make the purpose, technical solution and advantages of the implementation mode of the present invention clearer, the technical solution in the implementation mode of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the implementation mode of the present invention.
[0035] like Figure 1 As shown, it is a first embodiment of the utility model for optimizing the back ohmic contact structure of a GaN device by a sin insertion layer. In this embodiment, it includes a GaN substrate 10 and a sin layer 20 disposed on the back of the GaN substrate 10, wherein the sin layer 20 is provided with a concave-convex structure 30, and the concave-convex structure 30 is specifically a protrusion formed on the surface of the sin layer 20. The GaN substrate 10 is also provided with a metal contact layer 40, and the metal contact layer 40 is in contact with the concave-convex structure 30. The metal contact layer 40 is provided with a structure matching the protrusion on the surface of the sin layer 20, and the sin layer 20 and the metal contact layer 40 are physically interlocked through the concave-convex structure 30;
[0036] The concavo-convex structure 30 is periodically distributed on the surface of the sin layer 20 .
[0037] When in use, nanoimprint technology is used to form a micron or nanometer-level protrusion structure on the surface of the sin layer, and then a metal layer is deposited by sputtering. The metal layer forms a close contact with the top of the protrusion to achieve physical interlocking.
[0038] Among them, in the above technical solution, the depth of the concave-convex structure 30 ranges from 20nm to 100nm, and the width ranges from 80nm to 400nm.
[0039] When used, electron beam lithography technology is used to design and manufacture microstructures with a depth of 20nm to 100nm and a width ranging from 80nm to 400nm.
[0040] Furthermore, in the above technical solution, the cross-sectional shape of the concavo-convex structure 30 is columnar.
[0041] Furthermore, in the above technical solution, the concave-convex structures 30 are arranged in a rectangular shape, and the arrangement spacing is equal to 1 to 3 times the width range of the concave-convex structures 30 .
[0042] When in use, the concave-convex structure is manufactured according to a preset geometric pattern (such as a rectangular arrangement) using photolithography technology.
[0043] Furthermore, in the above technical solution, the thickness of the metal contact layer 40 is 100 nm to 300 nm.
[0044] Furthermore, in the above technical solution, the thickness of the sin layer 20 ranges from 20 nm to 80 nm.
[0045] The deposition thickness of the sin layer is precisely controlled by a chemical vapor deposition (CVD) process to ensure that it is within the range of 20nm to 80nm.
[0046] Furthermore, in the above technical solution, the contact area between the metal contact layer 40 and the sin layer 20 is increased to 1.2 to 3 times of the original plane contact area through the concave-convex structure 30 .
[0047] Furthermore, in the above technical solution, the concave-convex structure 30 is formed by nano-imprinting, electron beam lithography or laser interference lithography.
[0048] Furthermore, in the above technical solution, the ratio of the depth to the width of the concave-convex structure 30 is 0.5 to 2.
[0049] Furthermore, in the above technical solution, the metal contact layer 40 is made of titanium, aluminum, nickel, gold or alloys thereof.
[0050] like Figure 2 As shown, it is an example diagram of a second embodiment of the utility model for optimizing the back ohmic contact structure of a GaN device through a sin insertion layer. In this embodiment, it includes a GaN substrate 10 and a sin layer 20 disposed on the back of the GaN substrate 10, wherein the sin layer 20 is provided with a concave-convex structure 30, and the concave-convex structure 30 is specifically a protrusion formed on the surface of the sin layer 20. The GaN substrate 10 is also provided with a metal contact layer 40, and the metal contact layer 40 is in contact with the concave-convex structure 30. The metal contact layer 40 is provided with a structure matching the protrusion on the surface of the sin layer 20, and the sin layer 20 and the metal contact layer 40 are physically interlocked through the concave-convex structure 30;
[0051] The concavo-convex structure 30 is periodically distributed on the surface of the sin layer 20 .
[0052] When in use, nanoimprint technology is used to form a micron or nanometer-level protrusion structure on the surface of the sin layer, and then a metal layer is deposited by sputtering. The metal layer forms a close contact with the top of the protrusion to achieve physical interlocking.
[0053] Among them, in the above technical solution, the depth of the concave-convex structure 30 ranges from 20nm to 100nm, and the width ranges from 80nm to 400nm.
[0054] When used, electron beam lithography technology is used to design and manufacture microstructures with a depth of 20nm to 100nm and a width ranging from 80nm to 400nm.
[0055] Furthermore, in the above technical solution, the cross-sectional shape of the concave-convex structure 30 is conical.
[0056] Furthermore, in the above technical solution, the concave-convex structures 30 are arranged in a rectangular shape, and the arrangement spacing is equal to 1 to 3 times the width range of the concave-convex structures 30 .
[0057] When in use, the concave-convex structure is manufactured according to a preset geometric pattern (such as a rectangular arrangement) using photolithography technology.
[0058] Furthermore, in the above technical solution, the thickness of the metal contact layer 40 is 100 nm to 300 nm.
[0059] Furthermore, in the above technical solution, the thickness of the sin layer 20 ranges from 20 nm to 80 nm.
[0060] The deposition thickness of the sin layer is precisely controlled by a chemical vapor deposition (CVD) process to ensure that it is within the range of 20nm to 80nm.
[0061] Furthermore, in the above technical solution, the contact area between the metal contact layer 40 and the sin layer 20 is increased to 1.2 to 3 times of the original plane contact area through the concave-convex structure 30 .
[0062] Furthermore, in the above technical solution, the concave-convex structure 30 is formed by nano-imprinting, electron beam lithography or laser interference lithography.
[0063] Furthermore, in the above technical solution, the ratio of the depth to the width of the concave-convex structure 30 is 0.5 to 2.
[0064] Furthermore, in the above technical solution, the metal contact layer 40 is made of titanium, aluminum, nickel, gold or alloys thereof.
[0065] Specifically, the principle of the utility model is:
[0066] Physical interlocking design: By precisely forming micron or nanometer-scale protrusions on the surface of the sin layer, these protrusions form a physical embedded connection with the metal contact layer after deposition, which is equivalent to creating multiple "anchor points" on a microscopic scale, enhancing the bonding strength of the interface while expanding the actual contact area;
[0067] Interface engineering: Optimize the deposition process of the sin layer, such as using atomic layer deposition (ALD) technology to accurately control the thickness, purity and doping of the sin layer to reduce interface states and improve carrier transport characteristics, thereby improving contact quality and electrical performance;
[0068] Thermal Stress Management: Physical interlocking structures improve heat transfer by increasing the number and efficiency of heat flow paths, mitigate thermal stresses caused by mismatched thermal expansion coefficients, and reduce the risk of interface separation under thermal cycling.
Claims
1. A method for optimizing the back ohmic contact structure of a GaN device by inserting a sin layer, comprising a GaN substrate (10) and a sin layer (20) disposed on the back of the GaN substrate (10), characterized in that: The sin layer (20) is provided with a concavo-convex structure (30), the concavo-convex structure (30) being specifically protrusions formed on the surface of the sin layer (20), the GaN substrate (10) is further provided with a metal contact layer (40), the metal contact layer (40) is in contact with the concavo-convex structure (30), the metal contact layer (40) is provided with a structure matching the protrusions on the surface of the sin layer (20), and the sin layer (20) and the metal contact layer (40) are physically interlocked through the concavo-convex structure (30); Wherein, the concavo-convex structure (30) is periodically distributed on the surface of the sin layer (20).
2. The method of optimizing the back ohmic contact structure of a GaN device by inserting a sin layer according to claim 1, characterized in that: The depth of the concavo-convex structure (30) ranges from 20 nm to 100 nm, and the width ranges from 80 nm to 400 nm.
3. The method for optimizing the back ohmic contact structure of a GaN device by inserting a sin layer according to claim 2, characterized in that: The cross-sectional shape of the concavo-convex structure (30) is columnar, conical, pyramidal or corrugated, and the concavo-convex structure (30) is formed by nano-imprinting, electron beam lithography or laser interference lithography technology.
4. The method of optimizing the back ohmic contact structure of a GaN device by inserting a sin layer according to claim 3, characterized in that: The concave-convex structures (30) are arranged in a regular hexagon, rectangle or triangle, and the arrangement spacing is equal to 1 to 3 times the width range of the concave-convex structures (30).
5. The method of optimizing the back ohmic contact structure of a GaN device by inserting a sin layer according to claim 4, characterized in that: The thickness of the metal contact layer (40) is 100 nm to 300 nm.
6. The method of optimizing the back ohmic contact structure of a GaN device by inserting a sin layer according to claim 5, characterized in that: The thickness of the sin layer (20) ranges from 20 nm to 80 nm.
7. The method of optimizing the back ohmic contact structure of a GaN device by inserting a sin layer according to claim 6, characterized in that: The contact area between the metal contact layer (40) and the sin layer (20) is increased to 1.2 to 3 times the original plane contact area through the concave-convex structure (30).
8. The method of optimizing the back ohmic contact structure of a GaN device by inserting a sin layer according to claim 7, characterized in that: The ratio of the depth to the width of the concavo-convex structure (30) is 0.5 to 2.
9. The method of optimizing the back ohmic contact structure of a GaN device by inserting a sin layer according to claim 8, characterized in that: The metal contact layer (40) is made of titanium, aluminum, nickel, gold or alloys thereof.