Rapid SiO2 Atomic Layer Deposition Using Tris(tert-pentoxy)silanol

Rapid SiO2 atomic layer deposition (ALD) can deposit very thick and conformal SiO2 films by silanol exposure to surfaces covered with Al catalysts. In this study, we have explored the growth of rapid SiO2 ALD films using liquid tris(tert-pentoxy)silanol (TPS). The SiO2 film thicknesses were determined using quartz crystal microbalance and X-ray reflectivity measurements. The SiO2 film thicknesses deposited during one silanol exposure were dependent on the substrate temperature, silanol pressure, and silanol exposure time. The dependence of the SiO2 growth on these parameters helped to establish the mechanism of rapid SiO2 ALD. For TPS exposures of 1 s, the SiO2 ALD growth rate was larger at lower temperatures and higher TPS pressures. SiO2 ALD thicknesses of 125−140 A were observed at the highest TPS pressures of ∼1 Torr at lower temperatures of 150 and 175 °C. Rapid SiO2 ALD is believed to result from the growth of siloxane polymer chains at the Al-catalytic sites and the cross-linking of these polymer c...