Welcome to the Water
The purpose of this module is to help the student understand how the actual chemical process of film deposition proceeds. The module concentrates on the low pressure chemical vapor deposition (CVD) of polycrystalline silicon (Si) proceeds from silane (SiH4) reactant, as a simple CVD reaction example.
The module explores how the critical parameters of SiH4 partial pressure and wafer temperature determine deposition rate, and why their sensitivites are substantially different (temperature usually being much more sensitive a determinant of deposition rate than is pressure). It further shows that the deposition rate depends on the time-dependent variables of temperature and partial pressure, which are in turn time-dependent functions of the changes made to equipment settings (e.g., MFC flow, throttle valve position, lamp heating power). The exercises provided will demonstrate: