Conformality of TEOS/O-3 SiO2 thin films has been found to be deposition region dependent when the films were deposited using a standard atmospheric pressure chemical vapor deposition (APCVD) linear injector system at similar to 400 degrees C. In previous work, flow-like step coverage was only observed away from the central gas injection area where ozone was delivered from the outer part. In this work, we employed a new injector port configuration where ozone was delivered from the central port and TEOS was delivered from the outer port. Tn this case, flow-like step coverage was observed directly under the gas injection, yielding a gap filling capability of a 0.2 mu m space between aluminum lines with a 3:1 aspect ratio and a 0.35 mu m space between PolySi-coated thermal oxide structures with a 2:1 aspect ratio. AU these results suggest strongly that the actual concentration distribution of gas species at the wafer surface including O-3, TEOS, and reaction intermediates generated upon gas mixing in the chamber can vary substantially with position depending upon the reactor geometry and flow configuration, leading to diverse surface characteristics such as conformality.