Low temperature plasma enhanced atomic layer deposition of conducting zirconium nitride films using tetrakis (dimethylamido) zirconium and forming gas (5% H2+95% N2) plasma

Zirconium nitride (ZrN) has the lowest bulk electrical resistivity and high thermal stability among group IV and V transition metal nitrides, which makes it a promising material for ULSI applications such as a diffusion barrier for Cu interconnects, contact metal in III-V semiconductor devices, and in high density memory structures. Plasma enhanced atomic layer deposition (PEALD) of conducting ZrN thin films using Zr[N(CH3)(2)](4) and forming gas (5% H-2 + 95% N-2) plasma is reported in this article. The growth per cycle (GPC) for every deposition was determined from analysis of dynamic in-situ spectroscopic ellipsometry (d-iSE) measurements. An experimental design is proposed for faster determination of ALD growth saturation curves. At substrate temperature of 150 degrees C, a GPC of 0.10 nm/cycle was observed for self-limiting ZrN PEALD growth. The electrical resistivity of ZrN films deposited on SiO2 substrate was found to be 559.5 +/- 18.5 mu Omega cm with negligible change in resistivity even after similar to 1000 h exposure to air. The metallic behavior of our ZrN films was evident from the free electron dispersion component in dielectric response, the broad band of photoelectron emission across Fermi level and the positive temperature coefficient for resistivity of 0.0088/degrees C. (C) 2015 American Vacuum Society.