VLSI Technology 2011
Conference paper

Impact of back bias on ultra-thin body and BOX (UTBB) devices


We present a detailed study of back bias (Vbb) impact on UTBB devices with a gate length (LG) of 25nm and BOX thicknesses (TBOX) of 25nm and 10nm, respectively. It is reported for the first time that the Vt is modulated by Vbb across a wide temperature range, from -40°C to 125°C. The device electrostatics and reliability, under various V bb are investigated. The short channel effect (SCE) is well maintained across the bias points. NFET GIDL and HCI both improve when negative bias is applied. The Vbb effect on ring oscillators' (ROs) performance, based on 100nm contacted gate pitch (CPP), and on a 0.08μm 2 6-T SRAM, based on 80nm CPP, are reported for the first time. Clear RO performance/leakage tradeoff and SRAM static noise margin (SNM) modulation by Vbb are observed. SNM of 206mV is achieved at Vdd=0.9V. © 2011 JSAP (Japan Society of Applied Physi.