Accumulation vertical HEMT device

Abstract

The invention belongs to the technical field of semiconductors, and relates to an accumulation vertical HEMT device. In the forward conduction state of the accumulation vertical HEMT device, a high-concentration electron accumulation layer is formed at the side wall of an insulated gate electrode structure so that conduction resistance of the device can be greatly reduced and the device is ensured to have great forward current driving capacity; and in the reverse blocking state, the effect of electric field concentration of the interface of the barrier layer and the buffer layer of the device can be effectively improved by the insulated gate electrode structure, and a new electric field peak is introduced to the tail end of the insulated gate electrode structure so that electric field distribution is enabled to be more uniform, and off-state breakdown voltage of the device can be enhanced. The preparation technology of the device is compatible with the conventional technology.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, and relates to an accumulation type vertical HEMT (High Electron Mobility Transistor, high electron mobility transistor) device. Background technique [0002] The existing high withstand voltage GaN HEMT structure is mainly a lateral device, and the basic structure of the device is as follows figure 1 shown. The device mainly includes a substrate, a GaN buffer layer, an AlGaN barrier layer, and a source, a drain, and a gate formed on the AlGaN barrier layer. The barrier layer forms a Schottky contact. However, for lateral GaN HEMTs, in the cut-off state, electrons injected from the source can pass through the GaN buffer layer to reach the drain, forming a leakage channel. Excessive buffer layer leakage current will cause early breakdown of the device and cannot fully utilize the GaN HEMT. The high withstand voltage advantage of the material limits the application of GaN HEMTs in high vo...

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Problems solved by technology

[0004] For conventional vertical GaN HEMTs, vertical devices cannot use 2DEG to achieve conduction, and the conduction current needs to flow through the buffer layer, which makes the on-resistance much higher than that of lateral devices; and the device mainly relies on the p-GaN current blocking layer and n -The PN junction formed between the GaN buffer layers is used to withstand the withstand voltage. In order to achieve a high breakdown voltage, the concentration of the n-GaN buffer layer should not be too high, but a low-concentration buffer layer will increase the on-resistance of the device, which greatly limits Therefore, conventional vertical GaNHEMT devices have a contradictory relationship between withstand voltage and on-resistance

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