A normally-off hemt device with a honeycomb groove barrier layer structure under a field plate and its preparation method

Abstract

A normally-off HEMT device with a honeycomb groove barrier layer structure under a field plate and a preparation method thereof, belonging to the field of semiconductor devices. Technical solution: sequentially grow a buffer layer, an i-GaN layer, an insertion layer, a barrier layer, and a gate dielectric layer on a semiconductor substrate, where a number of honeycomb grooves are etched in a local area of ​​the barrier layer, and the i-GaN layer One side is etched into a step layer, a source electrode is set on the step layer, a drain electrode is set on the other side of the i-GaN layer, a gate dielectric layer is set above the barrier layer, and one end of the gate dielectric layer is connected to the The drain electrode is contacted and connected, the other end covers and grows into the honeycomb groove, and extends to the source electrode, and a gate electrode is arranged on the gate dielectric layer and in the corresponding area of ​​the honeycomb groove, and the gate electrode extending toward the source electrode. Beneficial effects: the invention can realize stable, large threshold voltage and normally-off operation with low on-resistance of the HEMT device, while effectively reducing the off-state leakage of the device and improving the breakdown voltage of the device.

Description

technical field [0001] The invention belongs to the field of semiconductor devices, in particular to a normally-off HEMT device with a honeycomb groove barrier layer structure under a field plate and a preparation method thereof. Background technique [0002] With the steady development of the radio communication market and traditional military applications in recent years, transistors play an important role in many ways. At the same time, with the rapid development of semiconductor technology, the requirements for transistors are becoming more and more stringent. The third-generation semiconductor materials are widely used due to their characteristics of high breakdown electric field, high saturation electron velocity, high thermal conductivity, high electron density and high mobility. The III-V heterostructure represented by gallium nitride (GaN) (typically such as AlGaN / GaN) has a high concentration (10 13 cm -2 ), high mobility (2000cm 2 / (V s)), the two-dimensional ...

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Problems solved by technology

At the same time, the uniformity of etching is difficult to guarantee, which results in the low threshold voltage of some devices in large-area devices or even the failure to realize normally-off type.

The method of injecting fluorine ions into the AlGaN barrier layer uses the strong electronegativity of fluorine ions to repel the electrons in the channel under the gate to cut off the channel. This method will not damage the barrier layer, but due to the relatively high thermal stability of fluorine ions Weak, resulting in the device being unstable at high temperature

The technology adopted in the device manufacturing process of these two methods is poor in uniformity for large-area devices. At the same time, in order to increase the threshold voltage of the device, the barrier layer will be damaged, resulting in an increase in the on-resistance of the device.

The method of inserting a P-GaN layer under the gate is difficult to realize due to the high concentration of P-type doping, so the threshold voltage of the manufactured device is small and unstable

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