Study of the growth of ultrathin (≤100 A˚) silicon dioxide (SiO2) films by thermal pyrolysis of tetraethoxysilane (TEOS) has been conducted. The oxide growth follows a first‐order or near first‐order relationship with respect to partial pressure of TEOS. The reaction appears to proceed via heterogeneous decomposition with byproduct inhibition with no incubation period. An extremely slow growth process has been investigated for depositing the SiO2film with monolayer thickness control, which is considered to be a critical requirement for forming ultra‐large‐scale integrated devices. ©1995 American Institute of Physics.