Monte Carlo simulations of ion implantation damage process in silicon: arsenic, phosphorus, silicon, BF(2), and boron implants

In this dissertation is reported a unified physically based ion implantation damage model which successfully predicts both the impurity profiles and the damage profiles for a wide range of implant conditions for arsenic, phosphorus, silicon, BF$\sb2,$ and boron implants. In addition, the amorphous layer thicknesses predicted by this new damage model are also in excellent agreement with experimental measurements. This damage model simulates point defect diffusion and reactions at room temperature after each ion cascade for the first time, and is the most physical model in the literature to date within the framework of the binary collision approximation (BCA). Ion implantation has been the primary tool for introducing the dopants into crystal silicon, and this is expected to continue well into the future. In the mean time, the continuing effort of scaling the device feature size down to deep sub-micron dimensions ($<$0.25 $\mu$m) has required very compact and precise control of the dopant profiles. Implantation damage dictates the final dopant profiles in two ways: (1) The as-implant doping profiles depend on the damage due to the damage dechanneling effect. (2) The implant-induced damage is the major source for the transient enhanced diffusion (TED) during subsequent thermal annealing. Although ion implantation damage has been extensively studied for years, previous damage models fail to accurately predict the damage profiles due to simplified, incomplete physical models. In order to improve this situation, a new physically based ion implantation damage model (KADM) has been developed and implemented in the Monte Carlo simulator UT-MARLOWE Version 4.0. This damage model is based on the physics of point defects in silicon, and explicitly simulates the defect production, diffusion, and their interactions which include interstitial-vacancy recombination, clustering of same type of defects, defect-impurity complex formation, emission of mobile defects from clusters, and surface effects. New computationally efficient algorithms have been developed to overcome the barrier of the excessive computational requirements. This damage model has achieved remarkable success in accurately predicting both the impurity profiles and the damage profiles, as well as the amorphous layer thicknesses for arsenic, phosphorus, silicon, BF$\sb2,$ and boron implants. In order to increase the computational efficiency for Monte Carlo simulations, a very simplified damage model (Kinchin-Pease damage model) has also been developed. This model is based on the Kinchin-Pease formula, and is very computationally efficient. A speed improvement of up to an order of magnitude over previous damage models has been achieved with an accuracy equal to or better than that of the previous version of UT-MARLOWE. Based on this damage model, a simple but extremely powerful and general method for performing multiple implant simulations has been developed, and very good agreement with experimental data has been obtained.