Numerical study on the self-heating effects for vacuum/high-k gate dielectric tri-gate FinFETs

摘要

The self-heating effects (SHEs) for Vacuum Gate Dielectric (VGD) tri-gate FinFET compared with High-k (HK) Dielectric tri-gate FinFET were investigated here based on 3D numerical electro-thermal TCAD simulation method. Simulation results show that VGD device suffers from a fiercer SHEs than HK device which will result in larger saturation current degradation. It is due to the low thermal conductivity of the gas around the channel which impedes the heat diffusion to the sinks and increases the peak temperature in the hot spot region. The SHEs can be suppressed by increasing the width of gas gap and gas pressure, based on the analysis of the pressure-dependent thermal conductivity of the gas in Nano-gap. However, the increased gas gap width entails the loss of the gate control ability over the channel resulting in the severer short channel effects.