Three-dimensional multi-trench gate enhanced HEMT device and preparation method thereof

Abstract

The invention provides a three-dimensional multi-trench gate enhanced HEMT device and a preparation method thereof. The three-dimensional multi-trench gate enhanced HEMT device comprises a substrate, a heterojunction, a gate, a source and a drain, wherein the heterojunction is arranged at the upper part of the substrate; the gate is provided with a three-dimensional multi-trench gate structure formed by a plurality of U-shaped grooves; the three-dimensional multi-trench gate structure is formed by etching the heterojunction; the distances between adjacent U-shaped grooves are sequentially reduced in the direction from the drain to the source; and the lengths of the U-shaped grooves are sequentially increased. The preparation method comprises the following steps: manufacturing a wafer of the device; defining isolation between the active region of the device and the device; depositing a metal film in the areas of the source and the drain to obtain the source and the drain of the device; and locally etching a heterojunction layer to prepare the three-dimensional multi-trench gate structure, and depositing the metal film on the upper part of the three-dimensional multi-trench gate to prepare the gate. Compared with a conventional trench gate structure, by the three-dimensional multi-trench gate structure, the electron concentration at the lower part of the gate gradually changes to form gradient distribution; and electric field distribution of the gate area is optimized, so that the reverse withstand voltage of the device and the reliability in a high electric field are improved.

Description

technical field [0001] The invention relates to the field of semiconductor devices, in particular to a three-dimensional multi-groove gate enhanced HEMT device and a preparation method thereof. Background technique [0002] As one of the most popular wide-bandgap semiconductor materials, GaN has the characteristics of large bandgap, direct bandgap, and high electron mobility. It is widely used in power electronics, optoelectronics, and high-frequency electronic devices. In particular, a thin layer of AlGaN is grown on the surface of GaN to form an AlGaN / GaN heterojunction. Under the dual effects of spontaneous polarization and piezoelectric polarization, a high-concentration two-dimensional electron gas (2-DEG) is formed below the AlGaN / GaN heterojunction interface. The electron concentration, mobility, and saturation velocity in this region are large. High electron mobility transistors (HEMTs) based on AlGaN / GaN heterojunctions have excellent performance and have broad ap...

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Problems solved by technology

However, this type of device destroys the continuity of the AlGaN layer, and there are problems such as low effective utilization of the active area of ​​the device and low current density.

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