Normally-off HEMT device with longitudinal grid structure and manufacturing method thereof

Abstract

The invention relates to the field of semiconductor devices, and provides a normally-off HEMT device with a longitudinal grid structure and a manufacturing method thereof. The HEMT device comprises a substrate, a buffer layer, an i-GaN layer, a grid dielectric layer and a passivation layer arranged in an overlapped mode, a source electrode coated between the ladder-shaped lower layer and the grid dielectric layer, a barrier layer and a drain electrode coated between the ladder-shaped upper layer and the grid dielectric layer, a grid electrode coated between the grid dielectric layer and the passivation layer, a source electrode pad passing through the passivation layer and the grid dielectric layer sequentially to contact with the source electrode, and a drain electrode pad passing through the passivation layer and the grid dielectric layer sequentially to contact with the drain electrode, wherein one end of the i-GaN layer and one side deviating from the buffer layer is ladder-shaped; the grid electrode has a Z-shaped section, the upper level of the grid electrode is located above the ladder-shaped upper layer, and the lower level is located above the ladder-shaped lower layer. The length of a grid electrode opening channel can be reduced, the grid on-state resistance of the device is reduced, and normally-off operation is realized.

Description

technical field [0001] The invention relates to the field of semiconductor devices, in particular to a normally-off HEMT device with a vertical gate structure and a preparation method thereof. Background technique [0002] Power switching devices are the core components of power electronics technology, and have been widely used in many fields of industrial production and social life. As global environmental and energy issues become increasingly prominent, researching the next generation of high-performance and low-loss power switching devices is one of the effective ways to improve power utilization and alleviate the global energy crisis. The next generation of power switching devices requires high performance index stability, low gate on-resistance, high switching speed, and requires normally-off (enhanced) operation characteristics in terms of safety, energy saving and simplified circuit design. The next-generation normally-off power switching device with mature technolog...

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Problems solved by technology

[0005] The present invention mainly solves the technical problem that the existing normally-off HEMT devices cannot have uniform and stable large threshold voltage, low device on-resistance and high switching rate at the same time. In the off-type category, a normally-off HEMT device with a vertical gate structure and its preparation method are proposed to achieve stable and large-threshold voltage normally-off operation of the HEMT device while effectively reducing the on-resistance of the device

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