Hemt epitaxial structure with multi-quantum well high-resistance buffer layer and preparation method

Abstract

The invention discloses a high electron mobility field effect transistor (HEMT) epitaxial structure and a method thereof prepared by growing a p-i-n multi-quantum well heterojunction and having a high-resistance GaN-based buffer layer. Taking advantage of the large difference between the spontaneous polarization intensities of AlN and GaN, polarized doping is achieved by growing AlGaN with a graded Al composition to obtain p-type Al x Ga 1‑x N-layer and n-type Al z Ga 1‑z N layer and fixed component Al by high temperature growth y Ga 1‑y N layer, so as to obtain a p-i-n multi-quantum well heterojunction, in the p-i-n heterojunction, due to the existence of the built-in electric field, the i layer is a completely depleted region, thereby obtaining a low-carrier concentration The high-resistance GaN-based buffer layer can effectively reduce the leakage current of the buffer layer, and at the same time improve the crystal quality of the epitaxial material to improve the high-voltage characteristics of the device and reduce the useless power consumption of the device, which is suitable for practical production applications.

Description

technical field [0001] The invention relates to semiconductor material growth and epitaxial growth of device structure layers, in particular to a HEMT epitaxial structure and method with a high-resistance GaN-based buffer layer prepared by p-i-n multi-quantum well heterojunction. Background technique [0002] GaN-based high electron mobility transistors (HEMTs) are made of Al x Ga 1-x Heterojunction field effect transistors formed by N barrier and GaN channel layer, due to Al x Ga 1-x The interface between the N barrier and the GaN channel layer has a large spontaneous polarization and piezoelectric polarization discontinuity, so there are a large number of residual polarization charges at the heterojunction interface to form a high-concentration two-dimensional electron gas at the interface. al x Ga 1-x The composition, thickness, and crystal quality of the N-barrier layer are all key epitaxial parameters affecting GaN-based transistors. GaN-based HEMTs have the advan...

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Problems solved by technology

Generally, there are two ways to obtain high-resistance GaN-based epitaxial materials: one is to increase the p- Type impurity or defect energy level compensation background electron concentration to obtain a high resistance GaN layer; another method is to form deep energy level defects or provide holes to compensate the remaining Carriers to obtain a high-resistance GaN layer; the first method is to obtain a high-resistance GaN epitaxial layer by introducing defect impurities, so the quality of the epitaxial layer will deteriorate, and at the same time obtain a high-resistance GaN method by controlling the growth conditions. The device dependence is strong, and the repeatability is poor; the second method introduces metal impurities that have a memory effect and will pollute the reaction chamber. An MOCVD is required to grow high-resistance GaN, and the introduction of impurities will reduce the mobility of the channel 2DEG , affecting the device characteristics

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