A gallium nitride based field effect transistor and its preparation method

Abstract

The invention discloses a gallium nitride-based field effect transistor, comprising a substrate, a buffer layer, a gallium nitride (GaN) layer, an aluminum gallium nitride (AlGaN) layer sequentially stacked from bottom to top, and a A source electrode, a drain electrode and a gate electrode located therebetween on the aluminum gallium layer, the gate electrode is made of conductive diamond-like carbon (DLC), and in the conductive DLC, the sp2 bond is The content is greater than 50%. The invention uses diamond-like carbon as the gate material to reduce the spontaneous thermal effect of the gate region, improve the stability, and at the same time adjust the gate resistance and polarity by doping diamond-like carbon to achieve the purpose of enhanced operation. The invention also discloses a preparation method of the above transistor.

Description

Technical field [0001] The invention relates to a semiconductor device, in particular to a gallium nitride-based field effect transistor and a preparation method thereof. Background technique [0002] Gallium nitride (GaN) is a representative of the third generation of semiconductors. It has excellent electrical characteristics such as wide band gap, high breakdown field strength, and high saturated electron drift rate. It has gradually attracted attention in the field of semiconductor devices. Among them, GaN-based high electron migration High-speed transistor devices have become the first choice for high-frequency, high-voltage, high-temperature and high-power applications. The conventional GaN-based high electron mobility transistor uses a heterostructure of AlGaN / GaN to form a two-dimensional electron gas layer (2-DGE), and controls the two-dimensional electron by changing the gate voltage between the source and the drain. The electron concentration of the gas, thereby contr...

AI Technical Summary

Problems solved by technology

However, metals that are commonly used at present, such as tungsten (W), have good thermal stability, and their melting point can reach above 3400°C, but the work function is too low, resulting in poor Schottky contact.

As a commonly used metal, molybdenum (Mo) has a melting point above 2600°C, but its thermal stability is not good, so it is difficult to meet the demand.

[0004] In addition, gallium nitride transistors generally work in depletion mode. To achieve enhancement mode work, fluorine (F) plasma treatment, N 2 O plasma treatment, but the plasma damage caused by plasma treatment will cause insufficient stability of components

In addition, there is also a way to use Cascode, but the manufacturing process is complicated, the packaging is special, the process requirements are high, and the yield rate is low, so it is difficult to apply in practice

Images