Impact of local poly-Si gate depletion on Vth variation in nanoscale MOSFETs investigated by 3D device simulation

We have developed a model to evaluate the impact of local gate depletion on Vth variation. Our model realizes that when a large grain exists in a gate, Vth becomes high, which support the measured data. The sizes (L & W) dependences of Vth distributions due to the local gate depletion are also investigated and the averaging effect works in wide channel MOSFETs. We are going to use this model to clarify the Vth variation in MOSFETs quantitatively in future work.