Studies on optical, chemical, and electrical properties of rapid SiO2 atomic layer deposition using tris(tert-butoxy)silanol and trimethyl-aluminum

Abstract

Rapid SiO2 atomic layer deposition (ALD) was used to deposit amorphous, transparent, and conformal SiO2 films using tris(tert-butoxy)silanol (TBS) and trimethyl-aluminum (TMA) as silicon oxide source and catalytic agent, respectively. The growth rate of the SiO2 films drastically increased to a maximum value (2.3nm/cycle) at 200°C and slightly decreased to 1.6nm/cycle at 275°C. The SiO2 thin films have C–H species and hydrogen content (∼8at%) at 150°C because the cross-linking rates of SiO2 polymerization may reduce below 200°C. There were no significant changes in the ratio of O/Si (∼2.1) according to the growth temperatures. On the other hand, the film density slightly increased from 2.0 to 2.2 although the growth rate slightly decreased after 200°C. The breakdown strength of SiO2 also increases from 6.20±0.82 to 7.42±0.81MV/cm. These values suggest that high cross-linking rate and film density may enhance the electrical property of rapid SiO2 ALD films at higher growth temperature.