Growth mechanism of TiN film on dielectric films and the effects on the work function

We have investigated the growth mechanism of ALD-TiN film on different dielectrics and the resulting effective work function value. TiN nucleation rate and growth rate are found to be dependent on the dielectric films. TiN growth mechanism changed from 3-D type on SiO2 to layer-by-layer type on HfO2. The minimum TiN thickness required for a complete surface coverage varies according to the growth mechanism. Capacitor (MOSCAP) characterization revealed that the effective work function of TiN is dependent not only on dielectric films but also on the TiN thickness. The behavior of work function and fixed charge correlated with the growth mechanism of TiN on dielectric films.