NMOS Hot Carrier Stressed Current Degradation Due to Hydrogen Deactivation of Dopant Determined by Junction Profiling

NMOS (N-type metal-oxide-semiconductor) hot carrier drive current degradation failure mechanism was investigated by dual-lens electron holography and scanning capacitance microscopy (SCM). De-activation of phosphorus dopant was observed on the drain side of hot carrier stressed NMOS devices. From the measurements, hydrogen de-activation of dopants by hot carrier stress is hypothesized, and its mechanism is verified by investigating junction profile on an unstressed NMOS device with and without hydrogen plasmon treatment and with subsequent 400°C annealing. Phosphorus dopant deactivation was observed in the device after H2 plasma treatment at room temperature, same as the dopant de-activation on drain side of hot carrier stressed devices, while 400°C annealing led to dissociation of P-H (or H-Si-P) bond and the recovery of the device junction.