Design consideration of N-drift region doping concentration in high voltage VDMOS transistor

N-drift doping concentration has important contribution in determining the breakdown voltage and on-resistance of the device. It should be well considered because higher N- drift doping concentration can minimize the on-resistance of the device, but also lowering breakdown voltage of the device that expected to be high. It also has a proportional relationship with threshold voltage degradation caused by hot carrier injection. So the variation of N-drift doping concentration can be used to optimize the VDMOS transistor performance

Compatibility Analysis of Silicon Nitride and Silicon Dioxide on HCI induced LDD MOSFET

Hot-carrier-injection (HCI) is one of important reliability issue under short-channel effect in modern MOSFET devices especially in nano-scaled CMOS technology circuits. The effect of the hot carrier can be reduced by introducing Lightly-Doped-Drain (LDD) structure on the device. The objective of this project is to study the effect of hot carrier in the LDD n-MOSFET. The LDD n-MOSFET is stressed with bias voltage at intervals of stressing time to determine the degradation model in the threshold voltage and drain current. From the parametrical analysis, it shows that the shift in threshold voltage and degradation in the drain current occurred after the MOSFET device is stressed with hot carrier stress test. The rate of threshold voltage shift and degradation of the drain current are dependence to the stressing time applied to the MOSFET device. The hot carrier stress test shows that the device with Si3N4 has smaller voltage shift compared to SiO2 material