Localization and Diffusion of Atomic Silicon in Delta-Doped GaAs Using Rapid Thermal Annealing

Silicon donor impurities with an initial Dirac-delta-function- like doping profile are diffused into GaAs using rapid thermal annealing. The diffusion of Si is determined by a novel method which is based on capacitance- voltage (CV) measurements and complimentary self-consistent calculations of the free-carrier distribution. Quantum-capacitance measurements probe with good approximation the position expectation value of a quantized electron system. Our technique allows us to determine diffusion on a 10angstroms scale and is more sensitive than other techniques such as secondary ion mass spectroscopy (SIMS).