Tetraethylorthosilicate (TEOS) oxide films were deposited in close proximity to an active device silicon substrate using low-pressure chemical vapor deposition (LPCVD) and plasma-enhanced chemical vapor deposition (PECVD) processes. It was observed that thermal anneal of the PECVD TEOS oxide in oxygen had resulted in less boron depletion and also tracked with the resistor sheet rho. The depletion mechanism was shown to be due to the film porosity difference between the two TEOS oxide films, which permitted 40 to 50% more silicon consumption underneath the LPCVD TEOS during film anneal in oxygen. TEOS oxide annealed in nitrogen ambient was shown to result in further boron depletion reduction as expected.