Longitudinally-conductive GaN (gallium nitride) normally-closed MISFET (metal integrated semiconductor field effect transistor) device and manufacturing method thereof

Abstract

The invention discloses a longitudinally-conductive GaN (gallium nitride) normally-closed MISFET (metal integrated semiconductor field effect transistor) device and a manufacturing method thereof. The device successively comprises a substrate (1), an n-type GaN layer (2), an electronic barrier layer (3), a non-doped GaN layer (4) and a heterostructure potential barrier layer (5) from bottom to top, wherein a groove is etched in the n-type GaN layer from the surface of the heterostructure potential barrier layer; a p-type GaN layer is formed on the groove by secondary growth so as to realize a grid conducting channel (7); two ends of the heterostructure potential barrier layer form source electrodes (9); an insulating layer (8) is covered on the grid conducting channel and the exposed surface of the heterostructure potential barrier layer; a grid electrode (11) is covered at a channel position on the insulating layer; and drain electrodes (10) are covered on the underside of the substrate. In the invention, a two-dimensional electron gas heterostructure with high concentration is taken as an access area, thus effectively reducing the on resistance; and the thin p-type GaN layer is formed in the etching groove by secondary growth, thus being easy to improve the threshold voltage and channel mobility of the longitudinally-conductive normally-closed MISFET.

Description

technical field [0001] The invention relates to the field of semiconductor devices, in particular to a vertically conducting GaN normally-off MISFET device and a manufacturing method thereof. Background technique [0002] Compared with Si materials, GaN semiconductor materials are more suitable for making high-power Power switching devices with large capacity and high switching speed are ideal substitutes for the next generation of power switching devices. [0003] The GaN material has a strong polarization effect, and the interface of the AlGaN / GaN heterojunction grown in the polarization direction forms a 10 13 cm -2 The two-dimensional electron gas (2DEG) with high concentration and high electron mobility makes AlGaN / GaN heterojunction field effect transistors (HFETs) have extremely low on-resistance, which is very suitable for making power switching devices. Therefore, it is an important subject to realize the practical goal of GaN power switching devices to prepare h...

AI Technical Summary

Problems solved by technology

[0007] From the above reports, the on-resistance of GaN-based recessed gate vertical conduction normally-off devices is still relatively high, and the electron mobility in the channel is relatively low, which is mainly due to the formation of grooves in the heterostructure by ICP etching. During the process, damage to the lattice at the edge of the groove

In the working engineering of the device, the edge of the groove is used as a conductive channel. Due to the influence of the damaged lattice, the on-resistance of the device becomes larger and the electron mobility of the channel decreases.

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