最大振荡频率为200GHz的蓝宝石衬底AlGaN/GaN HEMT

摘要

A gate-recessed AlGaN/GaN high electron mobility transistor (HEMT) on sapphire substrate having fmax of 200GHz is reported.The gate-recessed device with a T-shaped gate exhibits a maximum drain current density of 1.1 A/mm,and a peak value of 421 mS/mm for extrinsic transconductance with minimum short-channel effects because of an InGaNback-barrier layer.A unity current gain cut off frequency(fr ) of 30 GHz and a maximum oscillation frequency(fmax ) of 105GHz were obtained.After removing SiN by wet etching,the fT of the device increase from 30 GHZ to 50 GHz and the fmax increases from 105 GHz to 200 GHz,which are the results of lower Cga and Cgd after removing of Si3N4.%报道了最大振荡频率为200 GHz的基于蓝宝石衬底的AlGaN/GaN高电子迁移率晶体管(HEMT).外延材料结构采用InGaN背势垒层来减小短沟道效应,器件采用凹栅槽和T型栅结合的工艺,实现了Ka波段AlGaN/GaNHEMT.器件饱和电流达到1.1 A/mm,跨导为421 mS/mm,截止频率(fT)为30 GHz,最大振荡频率(fmax)为105GHz.采用湿法腐蚀工艺将器件的Si3N4钝化层去除后,器件的Cgs和Cgd减小,器件截止频率提高到50 GHz,最大振荡频率提高到200 GHz.