Longitudinal short-opening grid channel-type HEMT device and preparation method thereof

Abstract

The present invention relates to the field of a semiconductor device and provides a longitudinal short-opening grid channel-type HEMT device and a preparation method thereof. The HEMT device comprises a substrate, a buffer layer, a first GaN layer, a second GaN layer, a second barrier layer, a first barrier layer, a dielectric layer, a source electrode, a drain electrode and a grid electrode, wherein the buffer layer is positioned on the substrate; the first GaN layer is positioned on the buffer layer; one side, whic is deviated from the buffer layer, of the first GaN layer is provided with a groove; the second GaN layer and the second barrier layer are sequentially embedded into the groove; the first barrier layer is positioned on the first GaN layer except for the groove; the dielectric layer is positioned on the first barrier layer and the second barrier layer; the source electrode and the drain electrode are in contact with the first GaN layer and the lateral surfaces of the source electrode and the drain electrode are sequentially in contact with the first barrier layer and the dielectric layer from bottom to top; and the grid electrode is in contact with the dielectric layer. According to the present invention, a normally-closed type operation mode of the HEMT device can be obtained; when a large threshold value voltage is realized, on resistance of the device is effectively reduced; and the grid electrode structure also has the characteristics of small capacitor, high switching speed of the device and the like.

Description

technical field [0001] The invention relates to the field of semiconductor devices, in particular to a vertical short open gate channel type HEMT device and a preparation method thereof. Background technique [0002] Power switching devices have broad application prospects in many fields such as renewable energy generation and power system control of military facilities. The performance of traditional silicon-based power devices has approached the theoretical limit of the material. As a typical representative of next-generation wide-bandgap semiconductor materials, gallium nitride (GaN) has the characteristics of large band gap, high critical breakdown electric field, high saturation electron drift rate and good chemical stability. Its heterostructure (represented by AlGaN / GaN) interface has a large density of interface polarization charges, which can induce a high density of two-dimensional electron gas (2DEG) (>10 13 cm -2 ) as a conductive channel, and because the G...

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Problems solved by technology

[0006] The present invention mainly solves the problem of the existing gate structure technical scheme formed by AlGaN barrier layer etching or fluorine ion implantation in normally-off HEMT devices, which respectively cause damage to the 2DEG channel interface used for current transport under the gate and the The increase of electron scattering in the channel leads to the technical problem that the on-resistance of the device becomes larger and the on-current decreases. A new type of vertical short-open gate channel type HEMT device and its preparation method are proposed, which can realize the normally-off type of the device. Large threshold voltage while effectively reducing the on-resistance of the device

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