20 nm high performance enhancement mode InP HEMT with heavily doped S/D regions for future THz applications

Abstract

The DC and RF performance of Lg = 20 nm enhancement mode (E-Mode) In0.7Ga0.3As/InAs/In0.7Ga0.3As composite channel high electron mobility transistor (HEMT) on InP substrate with heavily doped In0.52Ga0.48As source/drain regions (S/D) is compared with the performance of conventional HEMT structure. The other features of the device include the use of T-gate, thin layer of platinum sink into the barrier layer, double δ-doping technology and multilayer cap. The Sentaurus TCAD simulations performed at room temperature using physics based drift-diffusion carrier transport model shows that Lg = 20 nm, W = 2 × 10 μm device with heavily doped In0.52Ga0.48 As S/D regions exhibit a 14% improvement in transconductance (gm) and 15% improvement in drain current compared to conventional HEMT structure. Also the proposed device shows 25% improvement in cut-off frequency (fT) and 17% improvement in maximum oscillation frequency (fmax) compared to conventional HEMT structure and this excellent performance is achieved mainly due to the reduction of parasitics such as S/D resistances and also due to the low gate length.