HEMT (high electron mobility transistor) device with back field plate structure and preparation method of HEMT device

Abstract

The invention discloses an HEMT (high electron mobility transistor) device with a back field plate structure. The HEMT device comprises a silicon substrate, a GaN epitaxial layer, an AlGaN barrier layer and an Si3N4 passivated protection layer sequentially from bottom to top; a gate electrode, a source electrode and a drain electrode are arranged on the AlGaN barrier layer; a groove with the crosssection in a right trapezoid shape is formed in the silicon substrate; the groove opens downwards, and the top of the groove is the lower surface of the AlGaN barrier layer; a back field plate structure is arranged on part of lower surface of the silicon substrate, the slope of the groove and part of top of the groove. The invention also discloses a preparation method of the HEMT device adoptingthe back field plate structure. By use of substrate isolation and back field plate technologies, substrate breakdown of the device is avoided, the breakdown voltage of the GaN HEMT device is increased, the field intensity peak value of the drain side of the gate electrode is reduced, the cooling performance of the device is improved, and the HEMT device has important significance in realizing high-performance and high-reliability gallium nitride based devices.

Description

technical field [0001] The invention relates to a high electron mobility transistor (HEMT), in particular to a HEMT device with a back field plate structure and a preparation method thereof. Background technique [0002] Power electronic devices are widely used in many fields such as household appliances, industrial equipment, and automotive power supplies. The new generation of power electronic devices requires higher efficiency, higher power density and higher reliability under high temperature working environment. At present, silicon-based power devices, such as MOSFETs and IGBTs, are widely used in power electronic devices. However, after long-term development of silicon electronic power devices, the performance and the theoretical limit of its materials, the new generation of power electronic devices are facing huge challenges such as high voltage, high frequency and small volume. The third-generation semiconductor material GaN has the advantages of large band gap, hi...

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Problems solved by technology

[0005] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the object of the present invention is to provide a HEMT device with a back field plate structure, which not only solves the problem that the existing Si substrate HEMT high voltage operation is easy to break down at the silicon substrate, It also solves the problem of electrical breakdown and thermal breakdown on the drain side of the gate, and realizes the normal operation of the Si substrate HEMT at a voltage of 1kV

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