A laser annealing process for high-performance power MOSFETs

Abstract

We propose a new laser annealing process for forming P-Base-Junction (Here, P represents the type of impurity) in the trench gate power MOSFETs (Metal Oxide Semiconductor Field Effect Transistor). An equivalent shallow junction structure for P-Base-Junction with uniform impurity distribution is achieved by the green laser annealing process of pulse mode. By comparing the laser annealing with conventional RTA (Rapid Thermal Annealing), lower sheet resistance and higher impurity activation in the shallow junction have been confirmed.

Excimer laser annealing for low-voltage power MOSFET

“…Because of the extremely high diffusivity of dopants in liquid Si, the boron dopants can redistribute almost uniformly within the melted layer, up to the interface between the solid and liquid Si. 18,19) The following rapid recrystallization from the liquid phase enhances dopant substitutional activation and produces high free carrier density.…”