Multi-Zone Modeling of Impurity Redistribution in Ion-Implanted Materials.
Final rept. 14 Apr-15 Nov 82,
NOTRE DAME UNIV IN DEPT OF ELECTRICAL ENGINEERING
Pagination or Media Count:
Implanted impurity redistribution has been observed during annealing of many ion-implanted materials. Experimental evidence suggests some position dependence in the redistribution process. The tail region of ion-implanted impurity profiles usually exhibits faster diffusion than the near-surface region. In this paper, a mult-zone model for the redistribution of implanted impurities is presented. The implanted substrate is considered as a stratified medium with zones where a local diffusion equation is obeyed, and an effective diffusion coefficient is defined within each zone. The basic formulation of the model and its mathematical background are discussed. The multi-zone equations are solved using the Crank-Nicolson method. A computer program is used to generate a plot of the post-annealing redistributed impurity profile. The model is applied to the case of sulfur-implanted GaAs for dose range of 4 x to the 13th power to 4 x 10 to the 15th powersq cm, with energies of 120 keV and 300 keV. Good agreement is obtained between the computer generated profile and the SIMS experimental profile.
- Solid State Physics