Modeling uphill diffusion of Mg implants in GaAs using suprem-i v

Publisher Website
Google Scholar
Abstract
Transient, uphill diffusion of implanted Mg in GaAs during a 900 °C anneal is simulated using suprem-iv. The diffusion is believed to occur via the substitutional-interstitial-diffusion (SID) mechanism, with excess interstitials and vacancies produced by the implantation process causing this abnormal diffusion behavior. The SID mechanism is shown to be equivalent, in terms of the governing equations, to the interstitial-dopant pair diffusion model used in suprem-iv. This allows one to use suprem-iv, a silicon process simulator that includes dopant–point-defect interactions, to model uphill diffusion once the appropriate diffusivity and defect parameters are included. The profiles of excess interstitials and vacancies produced by the implantation process are obtained from Boltzmann transport equation calculations. The transient uphill diffusion phenomenon can be well simulated using the diffusion model in suprem-iv, with the dopant diffusing from the region of excess interstitials toward the surface and the region of excess vacancies. Once the defect concentrations return to their steady-state levels, either by diffusion, recombination, or capture by sinks, the normal concentration-dependent diffusion into the substrate occurs.

This publication has 19 references indexed in Scilit: