Terminal structure applied to N-P type epitaxy
By designing an NP-type epitaxial structure and a multi-trench terminal structure and optimizing the electric field distribution, the problem of insufficient performance of NP-type epitaxial devices in the existing technology is solved, and the performance of devices with high voltage resistance and robustness is improved.
Patent Information
- Application Number
- CN202510795151.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-15
- Publication Date
- 2025-10-24
AI Technical Summary
The existing technology lacks a terminal structure for NP-type epitaxy, which limits the performance improvement of the device, especially in high-power, high-voltage, high-frequency, and high-temperature applications.
A NP-type epitaxial terminal structure was designed, including a drain, substrate, N-epitaxial layer, P-epitaxial layer, source, and a second dielectric layer. An N-type channel and trench were set in the P-epitaxial layer, and a first dielectric layer and polysilicon gate were laid on the inner sidewall of the trench. The electric field distribution was optimized by controlling the width and depth of the trench. Combined with the P-epitaxial layer being divided into two layers of different concentrations, P-base1 and P-base2, the charge distribution was optimized.
The device's voltage resistance is improved to meet the 1200V level requirements, with good robustness and terminal efficiency, improving the stability and performance of the device and avoiding leakage problems caused by high electric fields extending to the dicing lanes.
Smart Images
Figure CN120835599A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of semiconductors, and particularly relates to a terminal structure applied to N-P type epitaxy. BACKGROUND
[0002] In recent years, wide-bandgap semiconductor materials such as SiC, GaN, gallium oxide (Ga2O3), diamond (C) and aluminum nitride (AlN) have more advantages than Si in physical properties such as band gap, breakdown field strength and electron saturation drift speed. The prepared power devices such as diodes, transistors and power modules have more excellent electrical properties, can overcome the defects that silicon-based devices cannot meet the application requirements of high power, high voltage, high frequency and high temperature, and are one of the breakthrough paths to surpass Moore's Law, and are widely used in new energy fields.
[0003] In recent years, some structures using N-P type epitaxy have been proposed to improve the reliability of device gate oxide and solve the problem of high-energy ion implantation limiting production capacity, but no terminal structure specifically for N-P type epitaxy has been proposed, which limits the performance of the device. SUMMARY
[0004] In view of this, the application provides a terminal structure applied to N-P type epitaxy, which has a similar electric field change trend to that of a conventional multi-zone JTE terminal structure, and has good robustness.
[0005] To achieve the above-mentioned purpose, the application adopts the following technical scheme: The application provides a terminal structure applied to N-P type epitaxy, which comprises a drain, a substrate, an N-epitaxial layer, a P-epitaxial layer, a source and a second dielectric layer, the substrate is located on one side of the drain; the N-epitaxial layer is located on the side of the substrate away from the drain; the P-epitaxial layer is located on the side of the N-epitaxial layer away from the substrate, the P-epitaxial layer comprises an N-type channel and a plurality of grooves, the N-type channel is arranged through the P-epitaxial layer, one end of the N-type channel is in communication with the N-epitaxial layer, and the other end is in communication with the side of the P-epitaxial layer away from the N-epitaxial layer, the opening of each groove is located on the side of the P-epitaxial layer away from the N-epitaxial layer, the N-type channel and the inner wall of each groove are both coated with a first dielectric layer, and N-type ions are implanted in the N-type channel, and a polysilicon gate is arranged in each groove; the source and the second dielectric layer are both located on the side of the P-epitaxial layer away from the N-epitaxial layer, and the other end of the N-type channel and the opening of each groove are both in contact with the second dielectric layer.
[0006] Preferably, the P-epitaxial layer comprises P-base1 and P-base2, the P-base1 is located on the side of the N-epitaxial layer away from the substrate, the P-base2 is located on the side of the P-base1 away from the N-epitaxial layer, the ion concentration of the P-base2 is lower than that of the P-base1, and the N-type channel and the plurality of trenches are located on the P-base2.
[0007] Preferably, the thickness of the P-base1 is 0.2-0.5 μm; and / or, The ion concentration of the P-base1 is 1e17-5e17 cm -3 ; and / or, The thickness of the P-base2 is 1.5-2 μm; and / or, The ion concentration of the P-base2 is 2e16-5e16 cm -3 .
[0008] Preferably, the P-epitaxial layer comprises P-base1, and the N-type channel and the plurality of trenches are located on the P-base1.
[0009] Preferably, the plurality of trenches have the same width.
[0010] Preferably, the plurality of trenches are arranged in a manner that the width increases gradually, the width of the trench close to the N-type channel is 3 μm at most, and the width of the trench away from the N-type channel is 1 μm at least.
[0011] Preferably, the trench with a larger width has a larger depth.
[0012] Preferably, the N-type ion concentration in the N-type channel is 5e16-1e17 cm -3 .
[0013] Preferably, each trench is in communication with the P-epitaxial layer through the N-type channel.
[0014] Preferably, a P-type shielding layer is arranged between the trench and the N-type channel.
[0015] Compared with the prior art, the present application has the following beneficial effects: (1) The terminal structure of the N-P type epitaxy provided by the present application has a withstand voltage of more than 1800 V, which has met the demand of the current mainstream 1200 V level device. The electric field change trend of the device is similar to that of the conventional multi-zone JTE terminal structure, and the terminal structure has good robustness.
[0016] (2) The application controls the total amount of charges in the terminal area by the way of filling medium after trenching, and can control the number of charge reduction in different positions by controlling the width of the trench, so as to achieve the effect of multi-zone JTE, and improve the terminal efficiency.
[0017] (3) The application provides a terminal structure for N-P type epitaxy, wherein the P type epitaxy is divided into two layers, which are P-base1 with high concentration below and P-base2 with low concentration above. The structure is ion implanted after trenching in the outermost periphery of the terminal, so as to disconnect the P type area and avoid the high electric field extending to the position of the scribe lane to cause the device to leak. And, due to the low concentration of P-base2, the scattering during ion implantation can make the P type inversion near the trench sidewall and the corner into N type, without additional implantation times. In this way, a structure similar to JTE terminal is formed between the outermost trench and the active area. BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 The terminal structure for N-P type epitaxy provided by an embodiment of the application; Figure 2 The terminal structure for N-P type epitaxy provided by an embodiment of the application in the manufacturing process; Figure 3 The terminal structure for N-P type epitaxy provided by an embodiment of the application with multiple N type channels; Figure 4 The terminal structure for N-P type epitaxy provided by an embodiment of the application relative to Figure 1 Another terminal structure for N-P type epitaxy provided by an embodiment of the application; Figure 5 The manufacturing flowchart of the terminal structure for N-P type epitaxy provided by an embodiment of the application; Figure 6 The withstand voltage curve of the PiN diode structure simulated by the terminal structure for N-P type epitaxy provided by an embodiment of the application; Figure 7 The electric field distribution diagram of the terminal structure for N-P type epitaxy at the time of breakdown provided by an embodiment of the application; Figure 8 The electric field change curve diagram of the PN junction interface near the position of the red dashed line provided by an embodiment of the application.
[0019] Reference signs: the terminal structure for N-P type epitaxy 100, the drain 1, the substrate 2, the N-epitaxial layer 3, the P-epitaxial layer 4, P-base1 41, P-base2 42, the N type channel 5, the trench 6, the first dielectric layer 61, the polysilicon gate 62, the source 7, the second dielectric layer 8, the P type shielding layer 9. DETAILED DESCRIPTION
[0020] The application will be further described in connection with the specific embodiments below so that those skilled in the art can more clearly understand the application.
[0021] In recent years, SiC, GaN, gallium oxide (Ga2O3), diamond (C), aluminum nitride (AlN), and other wide-bandgap semiconductor materials have more advantages than Si in terms of bandgap width, breakdown field strength, electron saturation drift speed, and other physical properties. The prepared power devices such as diodes, transistors, and power modules have more excellent electrical properties, and can overcome the defects of silicon-based devices that cannot meet the application requirements of high power, high voltage, high frequency, high temperature, etc. It is also one of the breakthrough paths to surpass Moore's Law, and is widely used in the new energy field.
[0022] In recent years, some N-P type epitaxial structures have been proposed to improve the reliability of the gate oxide of the device and solve the problem of high-energy ion implantation limiting production capacity, but there is no terminal structure specifically for N-P type epitaxy at present, which will limit the performance of the device.
[0023] To solve the above technical problems, in combination with Figures 1-5 The application provides a terminal structure 100 applied to N-P type epitaxy, which comprises a drain 1, a substrate 2, an N-epitaxial layer 3, a P-epitaxial layer 4, a source 7 and a second dielectric layer 8, the substrate 2 is located on one side of the drain 1; the N-epitaxial layer 3 is located on the side of the substrate 2 away from the drain 1; the P-epitaxial layer 4 is located on the side of the N-epitaxial layer 3 away from the substrate 2, the P-epitaxial layer 4 comprises an N-type channel 5 and a plurality of grooves 6, the N-type channel 5 is arranged through the P-epitaxial layer 4, one end of the N-type channel 5 is in communication with the N-epitaxial layer 3, and the other end is in communication with the side of the P-epitaxial layer 4 away from the N-epitaxial layer 3, the opening of each groove 6 is located on the side of the P-epitaxial layer 4 away from the N-epitaxial layer 3, the N-type channel 5 and the inner wall of each groove 6 are both coated with a first dielectric layer 61, and the N-type channel is injected with N-type ions, and each groove 6 is provided with a polysilicon gate 62; the source 7 and the second dielectric layer 8 are both located on the side of the P-epitaxial layer 4 away from the N-epitaxial layer 3, and the other end of the N-type channel 5 and the opening of each groove 6 are both in contact with the second dielectric layer 8.
[0024] In the above technical solution, the substrate 2 is the base part of the whole device, located on the side of the drain 1, providing support for the whole device. The N-epitaxial layer 3 is located on the side of the substrate 2 away from the drain 1, which provides a high electron mobility area for the device, which is beneficial to improve the conductivity and response speed of the device. The P-epitaxial layer 4 is located on the side of the N-epitaxial layer 3 away from the substrate 2. The P-epitaxial layer 4 is provided with a plurality of grooves 6, which are in contact with the second dielectric layer 8 through their openings, optimizing the electric field distribution of the terminal area.
[0025] The present application can significantly improve the performance of semiconductor devices by introducing N-P type epitaxial structure and combining multiple grooves 6 and N type channel 5 design, improve the durability, stability and high efficiency of the device, and has important promoting effect on the devices with high performance and high reliability in modern semiconductor industry.
[0026] Further, the P-epitaxial layer 4 includes P-base1 41 and P-base2 42, the P-base1 41 is located on the side of the N-epitaxial layer 3 away from the substrate 2, the P-base2 42 is located on the side of the P-base1 41 away from the N-epitaxial layer 3, the ion concentration of the P-base2 42 is lower than that of the P-base1 41, and the N type channel 5 and the plurality of grooves 6 are located on the P-base2 42. P-base1 41 is a P type epitaxial layer close to N-epitaxial layer 3, which has a higher ion concentration. High concentration of P type doping can enhance the shielding effect of electric field. P-base2 42 is a P type epitaxial layer located on the side of P-base1 41 away from N-epitaxial layer 3, which has a lower ion concentration. The doping concentration of P-base2 42 is lower, so the scattering during ion implantation can make the P type inversion near the sidewall and corner of groove 6 into N type, without additional times of implantation.
[0027] In some embodiments, the total charge amount of the terminal area is reduced by implanting N type ions. When the total amount of N type ions is implanted, the concentration is less than the ion concentration of P-base2 42, the implanted area is still P type, but the concentration is reduced; when the total amount of N type ion concentration is implanted, the concentration is greater than the ion concentration of P-base2 42, and the implanted area will be inverted into N type.
[0028] Further, the thickness of the P-base1 41 is 0.2-0.5μm, and in some embodiments, the ion concentration of the P-base1 41 is 1e17-5e17cm -3 In some embodiments, the thickness of the P-base2 42 is 1.5-2μm, and in some embodiments, the ion concentration of the P-base2 42 is 2e16-5e16cm -3 .
[0029] Further, the P-epitaxial layer 4 comprises a P-base1 41, and the N-type channel 5 and the plurality of trenches 6 are located on the P-base1 41. At this time, in order to form the N-type channel 5 near the outermost trench 6, it is necessary to perform inclined ion implantation on the sidewall of the trench 6.
[0030] Further, the plurality of trenches 6 have the same width, and in some embodiments, the plurality of trenches 6 are arranged at intervals, and the widths are gradually increased. The width of the trench 6 closest to the N-type channel 5 is 3 μm, and the width of the trench 6 farthest from the N-type channel 5 is 1 μm. This design can optimize the carrier distribution and the electric field distribution, and improve the overall performance of the device. In some embodiments, the trench 6 with a larger width has a corresponding larger depth. The plurality of trenches 6 have the same width, which can ensure the uniformity of the electric field distribution and help the device to maintain stable performance under standard working conditions.
[0031] Further, the N-type ion concentration in the N-type channel 5 is 5e16-1e17 cm -3 .
[0032] Further, each trench 6 is in communication with the P-epitaxial layer 4 through the N-type channel 5. The width of each trench 6 can be designed to be consistent, and the N-type channel 5 is formed by N-type ion implantation. The P-type island in the form of an inverted T is formed between the trenches 6, thereby achieving an effect similar to that of a field limiting ring terminal.
[0033] In combination Figure 5 , the application further provides a preparation method of the terminal structure 100 applied to N-P epitaxy. The specific steps are as follows: S1, growing an N-epitaxial layer 3 on a wide-bandgap semiconductor material (SiC / GaN / Ga2O3 / C / AlN, etc.) substrate 2; S2, forming P-base1 41 and P-base242 by ion implantation, secondary epitaxy, growing P-type oxide, etc. S3, etching the trenches 6 in the terminal area by dry etching. It should be noted that under the same etching conditions, the depth of the trench 6 will slightly increase as the width increases; S4, forming the N-type channel 5 and the P-type shielding layer 9 at the outermost trench 6 by ion implantation; S5, growing a first dielectric layer 61, growing and etching polysilicon, growing and etching a second dielectric layer 8; S6, depositing and etching a source electrode and depositing a drain electrode.
[0034] Performance test and results By Figure 6 It can be seen that the device of the application withstands voltage more than 1800V, which has met the demand of the current mainstream 1200V level device. Figures 7-8 It can be seen that the electric field change trend is similar to that of the traditional multi-zone JTE terminal structure. It can be seen that the maximum electric field is located near the main junction of the active region, which also proves that the terminal structure has good robustness.
[0035] The specific raw materials in the application are all existing substances, which can be directly purchased from the market.
[0036] The above are only the preferred embodiments of the present application, not for limiting the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A termination structure applied to an N-P type epitaxial layer, characterized by, The application relates to a semiconductor device, comprising: a drain electrode; a substrate located on one side of the drain electrode; an N-epitaxial layer located on the side of the substrate away from the drain electrode; a P-epitaxial layer located on the side of the N-epitaxial layer away from the substrate, the P-epitaxial layer comprising an N-type channel and a plurality of grooves, the N-type channel being arranged through the P-epitaxial layer, one end of the N-type channel being in communication with the N-epitaxial layer and the other end being in communication with the side of the P-epitaxial layer away from the N-epitaxial layer, the opening of each groove being located on the side of the P-epitaxial layer away from the N-epitaxial layer, the N-type channel and the inner wall of each groove being coated with a first dielectric layer, and the N-type channel being doped with N-type ions, and each groove being provided with a polysilicon gate; and a source electrode and a second dielectric layer, both being located on the side of the P-epitaxial layer away from the N-epitaxial layer, the other end of the N-type channel and the opening of each groove being in contact with the second dielectric layer.
2. The termination structure for N-P type epitaxy according to claim 1, wherein The P-epitaxial layer comprises a P-base1 and a P-base2, the P-base1 being located on the side of the N-epitaxial layer away from the substrate, the P-base2 being located on the side of the P-base1 away from the N-epitaxial layer, the ion concentration of the P-base2 being lower than that of the P-base1, and the N-type channel and the plurality of grooves being located on the P-base2.
3. The termination structure for N-P type epitaxy according to claim 1, wherein The thickness of the P-base1 is 0.2-0.5 mu m; and / or The ion concentration of the P-base1 is 1e17-5e17cm -3 ; and / or, The thickness of the P-base2 is 1.5-2 mu m; and / or The ion concentration of the P-base2 is 2e16-5e16cm -3 .
4. The termination structure for N-P type epitaxy according to claim 1, wherein The P-epitaxial layer comprises a P-base1, and the N-type channel and the plurality of grooves are located on the P-base1.
5. The termination structure for N-P type epitaxy according to claim 1, wherein The plurality of grooves have the same width.
6. The termination structure for N-P type epitaxy according to claim 1, wherein The plurality of grooves are arranged in a spaced manner, and the width gradually increases, the width of the groove close to the N-type channel being 3 mu m at the maximum, and the width of the groove away from the N-type channel being 1 mu m at the minimum.
7. The termination structure for N-P type epitaxy according to claim 6, wherein The groove with a larger width has a larger depth.
8. The termination structure for N-P type epitaxy according to claim 1, wherein The N-type channel has an N-type ion concentration of 5e16-1e17cm -3 .
9. The termination structure for N-P type epitaxy according to claim 1, wherein Each groove is in communication with the P-epitaxial layer through the N-type channel.
10. The termination structure for N-P type epitaxy according to claim 1, wherein A P-type shielding layer is arranged between the groove and the N-type channel.