AlGaN/GaN heterojunction Schottky diode device based on P-GaN cap layer and floating metal ring

Abstract

The invention discloses an AlGaN / GaN heterojunction Schottky diode device based on a P-GaN cap layer and floating metal ring composite structure. The AlGaN / GaN heterojunction Schottky diode device comprises a substrate, and a GaN buffer layer, a channel layer, an AlGaN barrier layer and a passivation layer which are sequentially arranged on the substrate, an anode and a cathode are respectively arranged on two opposite sides of the upper surface of the AlGaN barrier layer, at least one combined structure is arranged on the AlGaN barrier layer between the anode and the cathode, and each combined structure comprises a first P-type GaN cap layer, a second P-type GaN cap layer and a floating metal ring; the first P-type GaN cap layer and the second P-type GaN cap layer are arranged on the AlGaN barrier layer at intervals, and the floating metal ring covers the upper surfaces of the first P-type GaN cap layer and the second P-type GaN cap layer and the AlGaN barrier layer between the firstP-type GaN cap layer and the second P-type GaN cap layer. The device adopts a structure combining the P-GaN cap layer and the floating metal ring, inhibits the electric field concentration effect, weakens the peak electric field, and ensures that the electric field is distributed more uniformly in the transverse direction, thereby reversely improving the breakdown voltage.

Description

technical field [0001] The invention belongs to the technical field of semiconductor devices, in particular to an AlGaN / GaN heterojunction Schottky diode device based on a P-GaN cap layer and a floating metal ring. Background technique [0002] With the development of microelectronics technology, the third-generation wide-bandgap compound semiconductor materials represented by GaN rely on high critical breakdown field strength, high thermal conductivity, high saturation electron velocity, and good high temperature resistance and radiation resistance. It shows great potential in power devices. Theoretically, the critical breakdown electric field strength of Si is 0.6MV / cm, while the critical breakdown electric field strength of GaN is more than 5 times that of Si, so under the same area, GaN can withstand higher voltage and obtain greater power . [0003] At present, GaN-based Schottky diodes are mainly divided into: GaN matrix material Schottky diodes and AlGaN / GaN heteroj...

AI Technical Summary

Problems solved by technology

The floating metal ring structure is to deposit and form several floating Schottky metal electrodes between the cathode and cathode metals. When a reverse bias is applied, the space charge region of the cathode metal will increase with the increase of the reverse bias. Widening, when extending to the position of the floating metal ring, due to the equipotential effect of the floating metal ring, the lateral potential here changes slowly, and the corresponding electric field peak value in the Schottky contact area decreases, improving the electric field concentration effect and improving Reverse breakdown voltage, while the floating metal ring structure will not introduce other parasitic capacitance, but, due to the depletion effect of the floating metal ring Schottky metal, the series resistance will increase, which will have some impact on the forward characteristics

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