Enhanced elimination of extended defects associated with P/sup +/ and Ga/sup +/ implantation of SIMOX

Abstract

Summary form only given. Ion implantation doping of annealed SIMOX (separation by implantation of oxygen) wafers has been investigated. The dose of the phosphorus and gallium implants, 1*10/sup 16//cm/sup 2/ and 5*10/sup 14//cm/sup 2/, respectively, was such that the peak concentration exceeded the impurity solid solubility at the subsequent annealing temperature of 900 degrees C. The energy was adjusted so that the top 700 AA of the 1300 AA superficial silicon layer was amorphized. Both plan-view and cross-sectional TEM were used to investigate the subsequent defect annealing kinetics. No category III (regrowth related) defects were observed upon low-temperature (550 degrees C) solid phase epitaxy. Diffuse dark field TEM results indicate that a fine dispersion of oxide particles exists in the superficial silicon layer. Upon 900 degrees C annealing, enhanced elimination of the category II (end of range) dislocation loops was observed in both the SIMOX and silicon control wafers. This indicates that the high oxygen concentration in the superficial silicon layer does not retard the enhanced defect dissolution process. However, Hall effect and sheet resistivity results indicate that there is a significant decrease in the free carrier mobility as well as the electrical activation of these dopants in SIMOX. >