Investigation of f t and f max in Si and Si1–x Ge x based single and dual material double-gate Tunnel FETs for RF applications
M Pown and B Lakshmi
Abstract
This study optimizes Si1−x Ge x based double gate tunnel field effect transistor (TFET) for their high ON current (I on) and lesser sub-threshold swing and compares Si and Si1−x Ge x based single material double gate (SMDG) and dual material double gate (DMDG) TFETs. This study also measures the two RF performance metrics, unity gain cut-off frequency (f t) and maximum oscillation frequency (f max) by varying the structural parameters, gate length, gate oxide thickness, channel thickness and underlap. Compared to single material gate devices, dual material gate devices give higher I on without compromising the leakage current for both Si and Si1−x Ge x based TFETs. Si1−x Ge x based TFETs offers higher f t and f max compared to that of Si TFETs for all the structural parameter variations considered in this study. DMDG TFETs exhibit higher f t with respect to SMDG TFETs. SMDG TFETs offers more f max compared to DMDG TFETs due to the smaller values of output conductance
