Modeling of Tungsten Thermal Chemical Vapor Deposition

概要

論文の詳細を見る
Low-pressure chemical vapor deposition (LPCVD) of tungsten (W) film on silicon (Si) substrate was performed by reducing hexafluoride (WF_6) with hydrogen. This CVD system is known for its nonlinear dependence of growth rate on WF_6 concentration. This study adopted a simple surface-reaction model which assumes that the precursor, i.e., WF_6, in the gas phase adsorbs on solid surfaces and then the adsorbed WF_6 molecule is converted into tungsten solid film. The two kinetic parameters involved in the model are derived from the experimental results. The solidification rate constant (k_s) is equal to the growth rate at very high WF_6 concentrations. The adsorption rate constant (k_a) is derived from profile analyses of films grown in microtrenches under very low WF_6 concentrations by applying the conventional Monte Carlo simulation code, which is valid for linear surface-reaction systems. In the temperature range of 623 to 823 K, k_a and k_s have activation energies of 82 kJmol^<-1>, 66.1 kJmol^<-1>, respectively. A newly proposed Monte Carlo simulation for nonlinear reaction systems, in combination with the two kinetic parameters, can quantitatively predict the shape of film in microtrenches for a wide range of temperatures and WF_5 concentrations.
社団法人応用物理学会の論文
1999-05-15