The Effect of Implant Species on the Stability of Ion Implantation Damage
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THE EFFECT OF IMPLANT SPECIES ON THE STABILITY OF ION IMPLANTATION DAMAGE K.S. Jones, S. Prussin* and D. Venables Department of Materials Science and Engineering University of Florida Gainesville, FL 32611 *T.R.W. Electronics Group Redondo Beach, CA 90278
ABSTRACT A systematic study of the effect of the chemical species, implanted into silicon, on the stability of the residual damage has been performed. Plan-view and cross-sectional transmission electron microscopy (TEM) studies show that the stability of the end of range damage (category II) defects upon annealing depends dramatically upon the implant species. This is exemplified by the a comparison of 6 9 Ga and 72 Ge implants in which a decrease in the dislocation density by over four orders is noted for 6 9 Ga implants compared to 72 Ge implants after identical annealing cycles. Additional comparisons of species with similar atomic masses indicate that this destabilizing influence on the dislocation loops by the implant species is related to exceeding the solid solubility of the implanted species. As a result of this dislocation loop destabilization effect complete elimination of the dislocation loops can be realized after relatively short thermal cycling. Evidence is presented indicating that the precipitates which form upon exceeding the solid solubility (category V defects) are dissolving during this enhanced defect dissolution process. INTRODUCTION An enormous amount of work has been done studying the defects that arise from the implantation of silicon [1], [2],[3). The goal of this work was to better understand these defects so that efforts could be made to eliminate them. Understanding what influences the dislocation loop annealing kinetics has become of increasing importance as device dimensions decrease. The need to eliminate implantation damage with the least amount of concommitant diffusion of the implanted species during the anneal, is important for creating shallow device junctions and contacts. Because of the complex nature of the different origins of the extended defects, an in-depth study of the influence of the chemical species on the stability of the defects has met with
Mat. Res. Soc. Symp. Proc. Vol. 100. 91988 Materials Research Society
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little or no success. Recent advances[4] in our understanding of the different types[3],[5] (categories) of damage have made it possible to adjust the implantation conditions such that the defect concentration is minimized and only a single type of extended defect forms upon annealing (category II or end of This has made it possible to study the effect range defects). of chemical species on the defect annealing kinetics. This study, done in conjunction with T.R.W. Inc., involved samples. The species preparing approximately 2500 TEM implanted included Al, Si, P, Ga, Ge, As, Sb over a dose range of 1 x 1O' 4 /cm 2 to 1 x 10 16 /cm 2 and studied as a function of annealing time and temperature (900 0 C to 1100 0 C). Very few studies have actually reported elimination of implantation related extended defe
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