ALD of Hafnium Oxide Thin Films from Tetrakis(ethylmethylamino)hafnium and Ozone

Abstract

Hafnium oxide thin films were deposited from tetrakis(ethylmethylamino)hafnium (TEMAH) and ozone by atomic layer deposition (ALD) on 200 mm silicon wafers. The half-reaction shows good saturation behavior. However, gradual surface saturation is observed for the TEMAH half-reaction. Within wafer non-uniformity of less than 1% and step coverage of about 100% were achieved for trenches with aspect ratio of around 40:1. The film thickness increased linearly as the number of cycles increased. From susceptor temperatures of 160-420°C, the lowest deposition rate (Å/cycle) and the highest refractive index is observed at 320°C. The atomic ratio of hafnium to oxygen determined by Rutherford backscattering is 1:2.04 for the films deposited at 320°C. The carbon and hydrogen content determined by secondary ion mass spectroscopy (SIMS) decreased as the susceptor temperature increased from 200 to 320°C. Lower carbon and hydrogen levels were obtained in the control films made with than the films made with A reaction mechanism of the ALD process is discussed. The results show that an -based ALD deposition is promising for microelectronic applications. © 2005 The Electrochemical Society. All rights reserved.