Atomic layer deposition of gadolinium scandate films with high dielectric constant and low leakage current

Abstract

Gd Sc O 3 films were deposited on hydrogenated silicon substrates by atomic layer deposition. The films were pure and amorphous, both as-deposited and after a 5min anneal at 950°C. Cross-sectional transmission electron microscopy revealed a sharp, smooth interface between GdScO3 and Si. Capacitance and leakage current measurements on metal oxide semiconductor capacitors made from atomic layer deposited WN∕GdScO3 stacks showed that the amorphous GdScO3 films have a high dielectric constant (∼22), low fixed charge density, and low interface trap density. A film with 1nm equivalent oxide thickness also demonstrated that the leakage current density is less than 2mA∕cm2 at 1V gate bias.