Low pressure chemical vapor deposition of borophosphosilicate glass films produced by injection of miscible DADBS-TMB-TMP liquid sources.

This study is a follow-up of earlier work in which the concept of injecting miscible liquid precursors into an LPCVD reactor was implemented for the preparation of BPSG films from a mixture of tetraethylorthosilicate (TEOS), trimethyborate (TMB), and trimethylphosphite (TMP). The depletion effects encountered in the use of TMP are circumvented here by the substitution of diacetoxyditertiarybutoxysilane (DADBS) for TEOS. The choice of this less thermally stable SiO sub 2 precursor allows for a decrease in deposition temperature from approximately 700degrees down to 500C. In this lower temperature regime, BPSG deposits are shown to be uniform in terms of both thickness and composition across a wide isothermal zone.