Growth Kinetics and Crystallization Behavior of TiO[sub 2] Films Prepared by Plasma Enhanced Atomic Layer Deposition

Atomic layer deposition (ALD) of films from tetrakis(dimethylamido) titanium (TDMAT) or titanium tetraisopropoxide (TTIP) precursors was investigated. The growth kinetics, chemical composition, and crystallization behavior of the films were compared for combinations of the two precursors with three different sources of oxygen [thermal ALD using and plasma-enhanced ALD (PEALD) using or plasma]. For TDMAT, the growth rate per cycle (GPC) decreased with increasing temperature; while for TTIP with either water plasma or plasma, a relatively constant growth rate per cycle was observed as a function of substrate temperature. It was found that the crystallization temperature of the films depends both on film thickness and on the deposition conditions. A correlation was observed between the crystallization temperature and the C impurity concentration in the film. The films grown using a plasma exhibit the lowest crystallization temperature and have no detectable C impurities. In situ X-ray diffraction measurements were used to test the diffusion barrier properties of the layers and proved that all films grown using either or plasma are dense and continuous.