Investigation of the dosage effect on the activation of arsenic- and boron-implanted low-pressure chemical vapor deposition (LPCVD) amorphous-silicon films

Abstract

The dopant activation of arsenic- and boron-implanted low-pressure chemical vapor deposition (LPCVD) amorphous silicon (cu-Si) films, furnace-annealed with different annealing temperatures has been investigated. For the arsenic-implanted specimens with a dosage of 4 x 10(14) cm(-2), an increase of sheet resistance was observed with increasing annealing temperature for the temperatures range from 700 to 850 degrees C. The reverse annealing phenomenon is attributed to dopant segregation at grain boundaries and becomes less marked with heavier doped films (2 x 10(15) cm(-2)). Consequently for a dosage of 1 x 10(16) cm(-2), the sheet resistance exhibits a monotonic decrease with increasing annealing temperature. As for the boron-implanted specimens, the reverse annealing phenomenon is not observed. It means that dopant segregation is not significant for boron-implanted films.