Numerical Evaluation of Impurity Profile in Silicon

수치해법에 의한 실리콘에서의 불순물 분포의 산출

A computer program (DIFSIM: Diffusion SIMulator) was written to calculate the impurity profile, specifically boron and phosphorus, due to three different diffusion processes-predeposition, drive-in in inert ambient, and drive-in in oxidizing ambient. The vacancy mechanism including Fair and Tsai's theory for phosphDrus diffusion was widely incorporated for modeling various diffusion processes. The concentrationtependent oxidation rate was also explained using the vacancy model, while the oxidation - enhanced diffusion was mo dolled using catkins replacement mochanlsm . The simulation results using DIFSIM showed a fairly good agreement with the experimental data by adjusting some of the empirical parameters in the program. The results obtained using DIFSIM were compared with the results from SUPREM II.

Predeposition, 질소분위기 drive-in과 산소분위기 drive-in 공정에 의한 실리콘내에서의 boron과 Phosphorus의 일차원적 분포를 implicit 방법과 SOR(successive over-relaxation)방법을 이용하여 산출해 내는 컴퓨터 프로그램 (DIFSIM)을 작성하였다. 확산공정의 모델로는 vacancy mechanism을 사용하였으며, 특히 phosphorus의 경우에는 Fair와 Tsai의 이론을 이용하였다. 불순물 농도에 따른 산화막의 성장속도는 vacancy mechanism에 의하였으며, 산화에 의한 확산공정에의 영향(OED ; oxidation-enhanced diffusion)은 Watkins replacement mechanism으로 modelling하였다. DIFSIM을 이용한 결과는 실험결과와 상당히 잘 일치하였으며, SUPREM II외 결과와도 비교하여 보았다.