High-performance normally off AlGaN/GaN-on-Si HEMTs with partially recessed SiNx MIS structure

초록

Recessed MIS gate structures with SiNx gate dielectric layer were investigated for use in normally off AlGaN/GaN-on-Si high electron mobility transistors (HEMTs). The channel mobility and threshold voltage (V-th) instability were strongly affected by the recessed configuration. Employing a 30nm SiNx gate dielectric layer composed of 6nm PEALD and 24nm ICP-CVD films on a 2nm AlGaN recessed barrier layer resulted in excellent electrical and dynamic characteristics with reduced effective interface trap density. A maximum drain current density of 590mAmm(-1), an on-resistance of 0.75 mcm(2), and a breakdown voltage of >1100V were achieved for the gate-to-drain distance of 10m. Owing to the remaining AlGaN barrier layer under the recessed gate region of the partially recessed device, the interaction between MIS interface traps and channel electrons was suppressed effectively, resulting in improved channel mobility and V-th stability.

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