Doping profile optimisation in bulk FinFET channel and source/drain extension regions for low off-state leakage

摘要

Sub-threshold leakage, punch-through leakage and band-to-band tunnelling (BTBT) leakage are the main components of off-state leakage in extremely scaled bulk FinFETs. By using 3-D process and device simulations, this paper studied the effects of channel and source/drain extension doping profile on these three leakage currents in bulk n-FinFETs with triangular shaped fins. Punch-through stop layer (PTSL) and source/drain extension doping profile have been carefully designed to lower the sub-threshold leakage, punch-through leakage and BTBT leakage. With the optimisation of PTSL implant and source/drain anneal conditions, the optimised n-FinFET exhibits superior short channel control, <65 mV/dec sub-threshold slope and <20 mV/V DIBL, and extremely low off-state leakage, <30 pA/um.