Gallium nitride power semiconductor device with high threshold stability

Abstract

The invention discloses a gallium nitride power semiconductor device with high threshold stability, which comprises a substrate, a nucleating layer, a drift region, a channel layer, a barrier layer, afirst p-type gallium nitride cap layer, a metal source electrode and a metal drain electrode; the upper surface of the first p-type gallium nitride cap layer is provided with a second p-type galliumnitride cap layer, an n-type gallium nitride cap layer and a Schottky contact type metal gate electrode, and the upper surfaces of the second p-type gallium nitride cap layer and the n-type gallium nitride cap layer are provided with ohmic contact type metal gate electrodes; and the Schottky contact type metal gate electrode is in direct contact with the side wall of the ohmic contact type metal gate electrode. According to the invention, the charge storage phenomenon can be effectively eliminated under low gate voltage, and the device is ensured to have higher threshold stability under the working condition of repeated switching; therefore, the gate leakage of the device can be reduced under high gate voltage, and the device is ensured to have a long-term stable working state under high gate voltage.

Description

technical field [0001] The invention mainly relates to the field of power semiconductor devices, in particular, a gallium nitride power semiconductor device with high threshold value stability. Background technique [0002] Gallium nitride (GaN), as a representative of the third-generation semiconductor, has the characteristics of large band gap, high electron saturation drift velocity, high critical breakdown electric field, high thermal conductivity and small dielectric constant. Wide bandgap and high breakdown electric field strength can greatly increase the peak voltage that the device can withstand and increase the output power of the device; high electron saturation drift rate enables the device to adapt to higher operating frequencies; high thermal conductivity enables the device to withstand higher temperature, thus greatly improving the stability and reliability of the system. Among them, the high electron mobility transistor (HEMT) prepared by the two-dimensional ...

AI Technical Summary

Problems solved by technology

Using this technical means can take advantage of the good ohmic contact between the P-type GaN or P-type AlGaN layer and the metal gate. The charge in the gallium nitride layer is released quickly, which ensures the threshold stability of the device, but the ohmic gate contact essentially only exists by the P-type gallium nitride or P-type aluminum gallium nitride layer, the aluminum gallium nitride barrier layer and the nitride The PiN diode composed of a gallium channel layer, so when the gate voltage exceeds the turn-on voltage of the PiN diode, the gate current will increase rapidly, resulting in the normal operation of the device. The gate voltage does not exceed 3V, which makes the device subject to many restrictions in system use.

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