Study of RF Performance for Graded-Channel SOI MOSFETs

The RF performance of Graded-Channel (GC) SOI MOSFET is investigated using accurate 2D TCAD simulations. Intrinsic-gain, cut-off frequency, distortion/linearity and gm/Idperformance were compared for GC SOI MOSFETs at various channel geometry and doping considerations. We outline how RF characteristics may be optimized in GC SOI MOSFETs. It is shown that GC devices provide a superior RF performance in all figures of merit except for distortion/linearity characteristics. However, they are as susceptible to short channel effects (SCE) as undoped counterparts. In particular, the performance gain obtained by tailoring doping level and position in the graded channel may be ultimately offset by SCE if SOT-layer thickness and gate length are not set appropriately.