Metalorganic atomic layer deposition of TiN thin films using TDMAT and NH3

Abstract

TiN films were deposited by using the metalorganic atomic layer deposition (MOALD) method using tetrakis-dimethyl-amino-titanium (TDMAT) as the titanium precursor and ammonia (NH3) as the reactant gas. Two saturated TiN film growth regions were observed in the temperature ranges from 175 and 190 degreesC and from 200 and 210 degreesC. TiN films deposited by the MOALD technique showed relatively lower carbon content than films deposited by metalorganic chemical vapor deposition (MOCVD) method. TiN films deposited at around 200 C under standard conditions showed the. resistivity values as low as 500 muOmega-cm, which is about one order lower than the values for TiN films deposited by MOCVD using TDMAT or TDMAT with NH3. Also, the carbon incorporation and the resistivity were further decreased with increasing Ar purge time and flow rate. TiN films deposited at temperatures below 300 C showed amorphous characteristics. TiN film deposited on contact holes, about 0.4-mum wide and 0.8-mum deep, by using the MOALD method showed excellent conformal deposition with almost 100 % step coverage. This study demonstrates that the processing parameters need to be carefully controlled to optimiae the film properties when using the ALD technique and that TiN films deposited by using the MOALD method exhibited excellent film properties compared to those of films deposited by using other CVD methods.