Transmission electron microscopy on {113} rodlike defects and {111} dislocation loops in silicon-implanted silicon

Abstract

Plan-view and cross-sectional transmission electron microscopy have been used to study the microstructural evolution of {113} rodlike defects as well as their correlation with the formation of {111} dislocation loops in silicon implanted with 50 keV 3.6×1014 Si+/cm2 8.0 mA and rapid thermally annealed at temperatures ranging from 500 °C to 1100 °C for various times. It was determined that the size distribution of {113} defects is a log-normal Gaussian probability function. The nucleation, growth and dissolution of both {113} defects and {111} dislocation loops were observed. The nuclei of {113} defects form first and are circular interstitial clusters. The nucleation is homogeneous in the matrix at the crystalline side of the amorphous/crystalline interface and occurs at a temperature as low as 600 °C for 1 s. These circular nuclei grow into rods along the 〈110〉 direction in a {113} habit plane. It was found that the growth of {113} defects inclined to wafer surface is more preferable than that parallel to the surface. Similarly their dissolution is also faster. The dissolution strongly depends on annealing temperature. Most of them can last for more than 240 s at 800 °C but only 15 s at 900 °C. It was found that the formation of {111} faulted Frank dislocation loops is an independent event of nucleation and growth. This nucleation of {111} Frank dislocation loops does not occur until the {113} defects begin to grow along a 〈110〉 direction and/or dissolve into the matrix. This means that there is a period when {113} defects release interstitial point defects before the {111} dislocation loops nucleate from the matrix. The growth of {111} dislocation loops, together with {113} defects, is a nonconservative Ostwald ripening process. The {113} defects were found to disappear completely at 900 °C for 120 s, but the {111} dislocation loops disappear at 1100 °C for 60 s.