4H-SiC衬底AlGaN/GaN HEMTs台面隔离技术的改进

Improvements of mesa isolation techniques for AlGaN/GaN HEMTs on 4H-SiC substrate

摘要: 采用离子注入和ICP干法刻蚀相结合的台面隔离技术提高了4H-SiC衬底A lGaN/GaNHEMTs的直流特性和高频特性。与只采用干法刻蚀进行台面隔离的器件相比,相邻器件有源区之间的泄漏电流减少了两个数量级,栅肖特基泄漏电流在栅漏电压为-40V时由38.5μA减小到1.2μA,截止频率由3.2 GHz提高到6.7 GHz。分析了器件泄漏电流减小和频率特性提高的原因。

Abstract: The combination of ionic implantation and inductively coupled plasma（ICP） etch was adopted to form the isolation mesa of AlGaN/GaN HEMTs on SiC substrate.The direct-current and high frequency characteristics of the AlGaN/GaN HEMTs are improved remarkably.By comparing with HEMTs fabricated only by ICP mesa isolation,the leakage current between mesas is reduced by two orders,the leakage current of gate schottky is reduced from 38.5μA to 1.2μA at a gate-drain voltage of -40V,f_T is increased from 3.2 GHz to 6.7 GHz.