SILICON OXIDATION MODELING IN SEMICONDUCT OR-DEVICE FABRICATION

It is posible to pack a large number of semiconducor devices on one si licon chip. Each device must be electrically isolated from the others and this is achieved by the oxidation of silicon in the 'between devic e' or nonactive regions.The model that we study assumes that the oxide is an incompressible viscous fluid through which the oxidant diffuses , and includes a stress-dependent reaction coefficient. We consider on ly one space variable and time, and study the evolution of the concent ration profile and the moving boundaries. We present results for diffe ring values of the equilibrium concentration and for differing functio nal dependence of the stress-dependent reaction coefficient on the ext ernal pressure. To obtain these results we employed a numerical algori thm and derived approximate analytic solutions. These (asymptotic) ana lytic solutions agree well with the numerical solutions.