Sticking coefficient as a single parameter to characterize step coverage of SiO2 processes

The authors use a single parameter, the sticking coefficient (or reaction probability), to model the step coverage of low pressure chemical vapor deposited (LPCVD) SiO₂ films. Earlier studies show that a low sticking coefficient, instead of surface diffusion, is the key step coverage improving mechanism. A simulation program based on a hypothesized reaction mechanism has been written to simulate deposition profiles. The program is capable of simulating redeposition and surface diffusion. Simulated profiles, using a single sticking coefficient (SC), agree well with experimental oxide films deposited on a variety of different geometries. The coefficient depends strongly on the silicon source used, and its magnitude decreases with increasing temperature