Modeling of low-pressure deposition of SiO2by decomposition of TEOS

The deposition of SiO2from tetraethylorthosilicate (TEOS) in a hot-wall system at low-pressure conditions has been studied. A two-dimensional model has been developed considering a large number of silicon wafers standing perpendicular to the gas flow. This arrangement is preferred in fabrication technology. The model describes the influence of the relevant process parameters on the thickness distribution of deposited oxide across the wafers and from wafer to wafer. The qualitative dependency of calculated profiles on parameter variations agree with experimental results. By choosing suitable parameters oxide layers with thickness deviations as small as 1.6 percent on the wafer and from wafer to wafer have been achieved.