Plasma-enhanced atomic layer deposition of SnO2 thin films using SnCl4 and O2 plasma

• High quality SnO2 thin films were prepared by PEALD using SnCl4 and O2 plasma.
• PEALD-SnO2 thin films exhibited no Cl impurities and high film density.
• The electrical and corrosion properties of PEALD-SnO2 was evaluated.

SnO2 thin films were deposited by plasma-enhanced atomic layer deposition (PEALD) using SnCl4 and O2 plasma at the temperature between 150 and 350 °C. The self-limiting growth of PEALD-SnO2 was confirmed by a careful study of the growth kinetics at 350 °C. At optimized growth conditions, PEALD-SnO2 exhibited a saturated growth per cycle of 0.072 nm/cycle, which is almost two times higher than that deposited by thermal ALD using SnCl4 reported earlier. Regardless of the growth temperatures, there were no Cl impurities within the films. Furthermore, the film density of rutile SnO2 was comparable to bulk density. With those favorable properties of PEALD-SnO2, the lower electrical resistivity and improved corrosion resistance of the films were obtained at 350 °C.