Defects in Ge+-preamorphized silicon

This work studied the morphology and annealing behaviors of extended defect s in Si subjected to various Ge+ preamorphization and BF2+ implantation con ditions. The extended defects formed were near the specimen surface when Ge + implantation energy and dose amount were low. During subsequent annealing , the end-of-range (EOR) loops were enlarged and then moved out of the spec imen. High energy/low dose Ge+ implantation generated a damaged layer which initially transformed into a wide zone containing dislocation loops and ro dlike defects in the annealed specimen. As the annealing proceeded, the wid th of defective zone gradually shrunk so that most of the extended defects could be annihilated by defect rejection/recombination process. In addition to the category II defects found in previous investigations, hairpin dislo cations emerged in high energy/high dose Ge+-implanted specimens. In this s pecimen, rodlike defects and hairpin dislocations could be removed by annea ling, while the EOR loops became relatively inert so that their removal wou ld require high temperatures and/or long annealing times. Microwave plasma surface treatment was also carried out to form a nitride layer on specimen surface. Experimental results indicate that in addition to effectively redu cing the size of EOR loops, surface nitridation might serve as a vacancy so urce injecting vacancies into Si to annihilate the interstitials bounded by dislocation loops. Reduction in the defect size was pronounced when bias v oltage was added to the plasma process. However, radiation damage might occ ur with too high of a bias voltage. (C) 1999 American Institute of Physics. [S0021-8979(99)06322-7].