P type layer-based III nitride enhanced HEMT (High Electron Mobility Transistor) and preparation method thereof

Abstract

The invention discloses a p type layer-based III nitride enhanced HEMT (High Electron Mobility Transistor) and a preparation method thereof. The HEMT comprises a heterojunction mainly formed by a first semiconductor layer and a second semiconductor layer, and a source electrode, a gate electrode and a drain electrode connected with the heterojunction; a third semiconductor layer capable of forming a heterojunction with the second semiconductor layer is also distributed between the gate electrode and a barrier layer; an etching stop layer is also distributed between the third semiconductor layer and the second semiconductor layer; the composition material of the etching stop layer has a higher etching selectivity ratio than that of the third semiconductor layer, or, the composition material of an area, close to the third semiconductor layer, in the second semiconductor layer has a higher etching selectivity ratio than that of the third semiconductor layer. Due to the design of the invention, the p type gate technology implementation difficulty can be greatly reduced, the p type layer etching depth can be precisely controlled, electrical features of the device and the repeatability, the uniformity, and the stability of a chip manufacturing process are ensured, and mass production is facilitated.

Description

technical field [0001] The invention relates to a preparation process of a HEMT device, in particular to a preparation method of a Group III nitride enhanced HEMT using an etching stop layer. Background technique [0002] Compared with traditional silicon-based MOSFETs, high electron mobility transistors (High Electron Mobility Transistors, HEMTs) based on AGaN / GaN heterojunctions have the advantages of low on-resistance, high breakdown voltage, and high switching frequency, so they can be used in various It is used as a core device in similar power conversion systems, and has important application prospects in energy saving and consumption reduction. However, due to the polarization effect of the III-nitride material system, generally speaking, HEMTs based on AlGaN / GaN heterojunctions are depletion mode (normally on). When this type of device is applied to a circuit-level system, it needs Designing a negative polarity gate drive circuit to realize switching control of the ...

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Problems solved by technology

In the selective etching process, it is necessary to etch a large area of ​​the non-gate area, but if the etching uniformity cannot be effectively controlled, it is very easy to cause over-etching of the p-type layer in the local area, and local There may be under-etching in the region, and both of them will eventually lead to a decrease in the two-dimensional electron gas concentration in the region between the gate source and the gate drain of the device, and generate a large number of surface defect states, which will seriously affect the working of the device. On-resistance and dynamic characteristics when

Therefore, the p-type gate technology based on selective etching requires precise and controllable etching depth of the p-type layer in the non-gate area, which greatly increases the difficulty of the p-type gate technology and makes the repeatability of the technology (piece to piece between), uniformity (between different regions in the chip), and stability (between different rounds of processes) are difficult to guarantee

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