Rapid vapor deposition SiO2 thin film deposited at a low temperature using tris(tert-pentoxy)silanol and trimethyl-aluminum

Abstract

Rapid atomic layer deposition (ALD) SiO2 thin film was deposited at various temperatures (below 250 °C) using liquid tris(tert-pentoxy)silanol (TPS) as a SiO2 precursor and trimethyl-aluminum (TMA) as a catalyst. The rapid ALD SiO2 films showed saturated growth behavior similar to conventional ALD, exhibiting a high growth rate (35 nm/cycle) at 120 °C. As the growth temperature increased to 250 °C, the growth rate decreased slightly to 10.5 nm/cycle. This behavior may have originated from two competing growth mechanisms: the Al catalytic reaction vs. a cross-link reaction. There is no carbon and very little hydrogen in rapid ALD SiO2 films according to Rutherford backscattering spectroscopy (RBS) and elastic recoil detection (ERD). As the growth temperature increases, the Si–O stretch bond in the Fourier transmittance infrared spectroscopy (FTIR) results increases but the Si–OH stretch bond decreases simultaneously. The rapid ALD SiO2 films also show an amorphous phase and a smooth surface despite the very high growth rate. In addition, the SiO2 films exhibited excellent electrical properties despite the low growth temperatures, showing a low leakage current (2.5 × 10−11 A at 8 MV cm−1) and a high breakdown field (over 11 MV cm−1 at all growth temperatures). The obtained dielectric constant of the SiO2 films ranged from 6.14 to 4.15 as the growth temperature increased.