Some consequences of ion beam shadowing in CMOS source/drain formation

Under certain circumstances the shadowing of CMOS source/drain (S/D) ion implants by the gate material has been shown to lead to degradation of n-channel transistor characteristics. The orientation of the wafer with respect to the ion beam and the simultaneous diffusion of boron and phosphorus are key elements in explaining these experimental results. Two-dimensional simulations agree with experiment.