Publication

Abstract : Hafnium oxide (HfO2)(HfO2) thin films were deposited from tetrakis(ethylmethylamino)hafnium (TEMAH) and ozone (O3)(O3) by atomic layer deposition (ALD) on 200 mm silicon wafers. The O3O3 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 H2OH2O than the films made with O3.O3. A reaction mechanism of the TEMAH+O3TEMAH+O3 ALD process is discussed. The results show that an O3O3 -based ALD HfO2HfO2 deposition is promising for microelectronic applications. © 2005 The Electrochemical Society. All rights reserved.