Surface chemistry and film growth during TiN atomic layer deposition 4 using TDMAT and NH 3

22 Abstract 23 24 Surface chemistry and film growth were examined during titanium nitride (TiN) atomic layer deposition (ALD) using sequential 25 exposures of tetrakis-dimethylamino titanium (TDMAT) and NH . This ALD system is shown to be far from ideal and illustrates 3 26 many potential problems that may affect ALD processing. These studies were performed using in situ Fourier transform infrared 27 (FTIR) techniques and quartz crystal microbalance (QCM) measurements. Ex situ measurements also analyzed the properties of 28 the TiN ALD films. The FTIR studies revealed that TDMAT reacts with NH * species on the TiN surface following NH x 3 29 exposures to deposit new Ti(N(CH ) ) * species. Subsequent NH exposure consumes the dimethylamino species and regenerates 3 2 x 3 30 the NH * species. These observations are consistent with transamination exchange reactions during the TDMAT and NH x 3 31 exposures. QCM studies determined that the TDMAT and NH reactions are nearly self-limiting. However, slow continual growth 3 32 occurs with long TDMAT exposures. In addition, the TiN ALD growth rate increases continually with growth temperature. The 33 resistivities of the TiN ALD films were 010 mV cm and the densities were (3 gycm corresponding to a porosity of ;40%. 4 3