This study aims to define a better condition to enhance the stability of the as-deposited plasma-enhanced chemical vapor deposition borophosphosilicate glass (PECVD BPSG) film. Stability is discussed in terms of optimized film composition SiO2-B2O3-P2O3/P2O5. Stable oxygen-rich films show better flow ability, lower dopant fluctuation through the growing oxide, reduced film stress, and lesser nitrogen and hydrogen incorporation into the growing film. Optimization of the B/P ratio, along with a lower amount of hydrogen-related species, especially H2O, which is a catalyst for BPO4 defects, makes the film less vulnerable to defect formation. The film structure can be modulated by the deposition parameters to get optimized ratios of N2O/SiH4, P2O3/P2O5, and SiO2/P2O5. Special attention is paid to the BPSG films with low SiH4-precursor gas flow. The limited condition for SiH4 flow is also discussed.