Extraction of point defect parameters by quantitative transmission electron microscopy

Some of the key parameters used in process simulators are formation energy, diffusivity, and the concentration of Si self-interstitials. Unfortunately, experimental verification of these parameters is lacking. The experiments presented in this dissertation are designed to improve our understanding of the intrinsic point defect population and the role of the surface on excess point defect behavior. In order to compute the formation energy for self-interstitials in Si the equilibrium concentration of self-interstitials at various temperatures has been determined. Samples with thin (10 nm) buried boron layers were grown by molecular beam epitaxy (MBE) and samples with a buried type II dislocation loop layer were produced by Ge+ ion implantation into undoped MBE grown silicon. These samples were subjected to a 40 keV 1e14/cm 2 Si+ implant followed by anneals at temperatures between 685°C and 815°C for varying times. The loop layer was investigated to monitor the total flux of the interstitials as a function of time while the broadening of the boron layer profile was analyzed by secondary ion mass spectroscopy (SIMS) to determine the interstitial supersaturation. A combination of these two values provides an estimate of the equilibrium concentration of the Si interstitials. The results at various temperatures are then used to extract the enthalpy of formation of the Si interstitial. For the formation of p-n junctions required for 0.18 mum and smaller technologies, the effects of implant damage on dopant diffusion and extended defect formation become increasingly important. Surface effects on transient enhanced diffusion (TED) and the formation and evolution of extended defects has been studied as a function of varying implant parameters like implant temperature, dose rate and the thickness of the amorphous layer formed. The results presented have been explained by proposing an empirical model for defect evolution.