Self-limiting growth of tantalum oxide thin films by pulsed plasma-enhanced chemical vapor deposition

Abstract

Ta 2 O 5 thin films were fabricated by pulsed plasma-enhanced chemical vapor deposition (PECVD) with simultaneous delivery of O2 and the metal precursor. By appropriately controlling the gas-phase environment self-limiting deposition at controllable rates (∼1Å/pulse) was obtained. The process was insensitive to substrate temperature, with a constant deposition rate observed from 90to350°C. As-deposited Ta2O5 films under these conditions displayed good dielectric properties. Performance improvements correlate strongly with film density and composition as measured by spectroscopic ellipsometry and Fourier transform infrared spectroscopy. Pulsed PECVD eliminates the need for gas actuation and inert purge steps required by atomic layer deposition.