Undoped-Body Extremely Thin SOI MOSFETs With Back Gates

We present a detailed study of gate length scalability and device performance of undoped-body extremely thin silicon-on-insulator (ETSOI) MOSFETs with back gates. We show that short channel control improves with the application of back bias via a decrease in the electrostatic scaling length as the subthreshold charges move toward the front gate. We demonstrate that, even for undoped ETSOI devices with ~8-nm SOI thickness, the improvement in short channel control with the application of a back bias translates to 10% higher drive current, 10% shorter gate lengths, and, consequently, 20% lower extrinsic gate delay at a fixed off-state current of 100 nA/mum and a back oxide electric field of 1.5 MV/cm (0.5 MV/cm SOI field).