Rapid Thermal Annealing of As in Si

Abstract

ABSTRACTThe results of a detailed investigation of the diffusion of ion implanted As in Si during Rapid Thermal Annealing (RTA) are reported. A series of experiments has been performed on samples implanted with As in a wide range of concentrations. The use of an improved thermocouple bonding technique enables precise measurement and control of the temperature versus time cycle for each individual sample. The RTA apparatus is designed to perform high vacuum annealing, eliminating the complications associated with point defect generating mechanisms at the surface, which are known to influence the diffusion of impurities in Si. Sample analysis includes depth profiling by SIMS and RBS, and electrical characterization employing VanderPauw and Spreading Resistance measurements.The resulting profiles have been analyzed via a numerical solution of the diffusion equation subject to the appropriate boundary conditions. With an effective As diffusivity of the form we find good simulation of all measured profiles with the standard values of D0 and D- from SUPREMIII and a one parameter fit to D= Recent results on the redistribution of low dose As implants in heavily phosphorus doped Si illustrate the strong Fermi level dependence. The model has also been successfully used to simulate RTA data in the literature where careful temperature measurements have been made.