Removal of end-of-range defects in Ge+-pre-amorphized Si by carbon ion implantation

Abstract

Carbon ion implantation was employed to annihilate the end-of-range (EOR) defects in Ge+-pre-amorphized Si. Experimental results showed that the efficiency of EOR defect removal depends on the Ge+-pre-amorphization conditions, the location of projected range (R-p) of carbon implant and subsequent annealing conditions. The best defect removal occurred when R-p of carbon implantation was brought close to the amorphous/crystalline (a/c) interface generated by Ge+-pre-amorphization. The higher the annealing temperature, the better the interstitial gettering efficiency of carbon atoms was observed. However, transmission electron microscopy investigation revealed the emergence of hairpin dislocations when dose and accelerating voltage of Ge+ implantation were high. In specimens without carbon implantation, the hairpin dislocations could be readily removed by a 900 degrees C, 30 min anneal. For carbon-implanted specimens, the density of hairpin dislocations increased when R-p of carbon implantation was close to the (a/c) interface. The glide motion of hairpin dislocations was affected by Ge+-pre-amorphization conditions and was inhibited by the SiC complexes formed in the vicinity of dislocations so that they became rather difficult to anneal out of the specimens. (C) 1999 American Institute of Physics. [S0021-8979(99)06306-9].