Schottky diode based on non-polar GaN and preparation method thereof

Abstract

The invention discloses a Schottky diode based on non-polar GaN and a preparation method thereof. The diode comprises a GaN substrate, a vertical multi-channel layer located on the GaN substrate, a GaN cap layer located on the vertical multi-channel layer, an ohmic contact electrode located on the back surface of the GaN substrate and a Schottky contact electrode located on the GaN cap layer. The GaN substrate is a non-polar n type GaN body substrate; and the vertical multi-channel layer comprises a plurality of u-GaN channel layers and n-AlGaN barrier layers, and the u-GaN channel layers and the n-AlGaN barrier layers are arranged at intervals in the horizontal direction so as to form a parallel multi-channel structure perpendicular to the GaN substrate. The diode improves the crystal quality of the device, inhibits the generation of an electric leakage channel, increases the working current, and can be used for preparing diode devices for high-frequency, low-voltage and large-current rectification.

Description

technical field [0001] The invention belongs to the technical field of microelectronics, and in particular relates to a Schottky diode based on nonpolar GaN and a preparation method thereof. Background technique [0002] Schottky diodes are diodes made using the principle of metal-semiconductor junctions formed by the contact of metals and semiconductors. They are low-power, ultra-high-speed semiconductor devices. Due to its low conduction voltage and no reverse recovery problem, it is widely used in switching power supplies, frequency converters, drives and other circuits. Among them, GaN (gallium nitride)-based Schottky diodes have good development prospects in the power rectifier market due to their advantages such as fast switching speed, high field strength and good thermal characteristics. [0003] In the existing related technologies, GaN power devices are usually prepared by epitaxial AlGaN / GaN heterojunction on silicon carbide or silicon substrates. There is a pol...

AI Technical Summary

Problems solved by technology

[0004] However, GaN epitaxially grown on different substrates belongs to the lateral structure, because there is a large lattice mismatch between the heterogeneous substrate and GaN, there are different degrees of difference in thermal expansion coefficient, and some non-idealities in the process Factors make the heteroepitaxial GaN material have a high dislocation density, and these dislocation defects have been proved to be the current leakage channel and the main cause of leakage

On the other hand, the lattice mismatch between AlGaN and GaN will also indirectly reduce the 2DEG density and mobility in the heterojunction by affecting the crystal quality, thus affecting the device performance.

Images