Heterostructure Ge-Body pTFETs for Analog/RF Applications

This article presents a systematic study on the analog and radio-frequency (RF) performance of type-II staggered heterostructure ${p}$ -channel tunnel field-effect transistors ( ${p}$ TFETs) with Ge (Germanium) channel and different compound semiconductor source. In order to study the figure-of-merits (FOMs) of analog and RF performances, various Ge-channel ${p}$ TFETs are designed with Ge, GaAsP, SiGe, and InAlAs sources. The numerical simulation data show an improvement in the FOMs of analog performance such as drain current ( $I_{ds}$ ), transconductance ( $g_{m}$ ), transconductance-generation-factor ( $g_{m}$ /I $_{ds}$ ), and intrinsic gain ( $g_{m}$ $R_{o}$ ) of the devices with compound semiconductor source compared to Ge-source ${p}$ TFET devices. Similarly, an improvement in the RF FOMs such as gate-to-source ( $\text{C}_{gs}$ ) and gate-to-drain ( $\text{C}_{gd}$ ) capacitances, maximum frequency of oscillation ( $f_{MAX}$ ), and cutoff frequency ( $f_{T}$ ) is observed for the devices with GaAsP, SiGe, and InAlAs source compared to Ge-source ${p}$ TFETs. The simulation results also show that the common-source amplifiers, designed with Ge-heterostructure ${p}$ TFETs, exhibit a significant enhancement in gain and Gain-Bandwidth product of the circuit.