A vertical GaN-based heterojunction semiconductor device and its manufacturing method

Abstract

The invention provides a longitudinal gallium nitride-based heterojunction semiconductor device and a manufacturing method thereof. The device comprises a substrate, a metal layer and a longitudinal gallium nitride-based heterojunction, wherein the longitudinal gallium nitride-based heterojunction is located at a GaN side of the heterojunction and comprises a longitudinal two-dimensional electron gas; and the longitudinal two-dimensional electron gas serves as a current channel from the surface to the bottom surface when the device is switched on. The method comprises the following steps: depositing unintentionally doped gallium nitride buffer layer on the surface of the substrate; etching the unintentionally doped gallium nitride buffer layer by a lithography mask; depositing an aluminum gallium nitride barrier layer to form the longitudinal gallium nitride-based heterojunction; and forming a metal layer on the surface by the lithography mask. The device chip provided by the invention can provide relatively high and effective power per unit area, so that the product has relatively good cost performance; and the manufacturing method is simple and easy to achieve.

Description

technical field [0001] The invention relates to a semiconductor device, in particular to a gallium nitride semiconductor device. Background technique [0002] Third-generation semiconductor materials, including CdS, ZnO, SiC, GaN, diamond, etc. The bandgap of these semiconductor materials is greater than 2.2eV. In terms of electronic devices, the research on SiC and GaN is relatively mature, and it is currently a hot spot in the field of semiconductor materials and device research in the world. [0003] Gallium nitride (GaN) has a band gap of 3.4eV. The wide band gap enables GaN materials to withstand higher operating temperatures and also enables GaN materials to have a larger breakdown electric field. A larger breakdown electric field means that the device can withstand Higher operating voltage can improve the power characteristics of the device. GaN also has high electron saturation drift velocity and high thermal conductivity. Generally speaking, GaN is an excellent ma...

AI Technical Summary

Problems solved by technology

All electrodes of the lateral gallium nitride-based heterojunction semiconductor device are placed on the surface of the device, and the active region in the surface structure of the device is also used to withstand the reverse bias voltage applied to the device, if The higher the reverse bias voltage, the wider the surface active area needs to be used, which leads to the fact that the chip area utilization rate is not as effective as vertical high-voltage devices. In contrast, the average output power per unit area of ​​the surface of lateral devices is much smaller than that of vertical devices. Vertical high-voltage devices, which is a major disadvantage of lateral devices

[0009] figure 2 The front cross-sectional view of a GaN device including buried contacts proposed for US Patent No. US8,569,799B2, such as figure 2 As shown, the GaN device including a buried contact includes a substrate 110, an unintentionally doped gallium nitride (GaN) buffer layer 120, aluminum nitride (AlN) 130, aluminum gallium nitride (AlGaN) The barrier layer 140, the cap layer 150, the metal layer 160, and the conductive material 180 make the electrode distribution of the lateral device become similar to the vertical device, that is, the anode (high voltage) is on one side of the device, and the cathode (low voltage) is on the other side. On the one hand, the structure described in this patent is only a "quasi" vertical structure, still relying on the width of the active area on the chip surface to withstand the reverse bias voltage, and the utilization rate of the surface area is not much improved compared with the general lateral device

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