INFLUENCE OF DISLOCATION LOOPS CREATED BY AMORPHIZING IMPLANTS ON POINT-DEFECT AND BORON-DIFFUSION IN SILICON

An experiment has been pet-formed in which wafers with boron-doped, bu ried marker layers were implanted with 100 keV, 2 x 10(15) cm(-2) Si. This is an amorphizing implant. A second implant of B was introduced p rior to any post-implant annealing such that the implanted B was compl etely contained within the preamorphized region. After the implants, s amples were annealed at various temperatures for various times and sec ondary-ion mass spectroscopy was used to obtain the dopant profiles. I t was found that the buried market layer exhibited normal transient-en hanced diffusion behavior. However, the B in the preamorphized region did not experience any significant amount of motion. This suggests tha t the solid phase regrowth of the amorphous layer did not cause a redi stribution of the dopant atoms within that layer, and also the plane o f dislocation loops that form at the amorphous/crystalline interface i s an effective barrier against the interstitial damage diffusing upwar ds from the nonamorphized tail of the amorphizing Si implant. The same behavior was observed when As or P implants are used instead of the B implant. This type of behavior has been simulated using a model consi dering the growth of stacking faults bounded by dislocation loops. (C) 1995 American Institute of Physics.