REVERSE ANNEALING OF ARSENIC-IMPLANTED LOW-PRESSURE CHEMICAL-VAPOR-DEPOSITION (LPCVD) AMORPHOUS-SILICON FILMS

The reverse annealing of arsenic-implanted amorphous-silicon films has been observed. The dose dependence of this phenomenon is also investigated. For the specimens implanted with the dosage of 4 x 10(14) ion/cm(2), the sheet resistances show an increase in the annealing temperature range from 700 to 850 degrees C, which is attributed to the segregation of the activated dopants to the grain boundaries. This reverse annealing phenomenon is less prominent and the turnaround temperature is lower for the implantation dosage of 2 x 10(15) ion/cm(2), which is attributed to the effects of dopant segregation which decreases with increasing implantation dosage. Consequently, this reverse annealing phenomenon was not observed for the case of dosage of 1x10(16) ion/cm(2).