Gallium nitride based field effect transistor and preparation method thereof

Abstract

The invention discloses a gallium nitride based field effect transistor. The gallium nitride based field effect transistor comprises a substrate, a buffer layer, a GaN layer, an AlGaN layer, a source electrode, a drain electrode and a grid electrode located between the source electrode and the drain electrode which are sequentially stacked from bottom to top, wherein the source electrode and the drain electrode are arranged on the AlGaN layer, the grid electrode is made from conductive diamond-like carbon (DLC), and the spe key content in the conductive DLC is higher than 50%. The diamond-like carbon is used as a grid electrode material, so that the spontaneous heat effect of a grid electrode region is reduced, stability is improved, meanwhile a resistance value and polarity of the grid electrode are adjusted in a diamond-like carbon doping mode, and the purpose of enhanced work is achieved. The invention further discloses a preparation method of the transistor.

Description

technical field [0001] The invention relates to a semiconductor device, in particular to a GaN-based field effect transistor and a preparation method thereof. Background technique [0002] Gallium nitride (GaN) is a representative of the third-generation semiconductors. It has excellent electrical properties such as wide bandgap, high breakdown field strength, and high saturation electron drift rate. It has gradually attracted attention in the field of semiconductor devices. GaN-based high electron mobility High-rate transistor devices have become the first choice for high-frequency, high-voltage, high-temperature and high-power applications. The known GaN-based high electron mobility transistor uses the AlGaN / GaN heterostructure to form a two-dimensional electron gas layer (2-DGE), and controls two-dimensional electrons between the source and drain by changing the gate voltage. The electron concentration of the gas controls the working state of the transistor. [0003] In...

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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

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