Three-dimensional deposition of TiN film using low frequency (50 Hz) plasma chemical vapor deposition

Abstract

Titanium nitride (TiN) films have been deposited on three-dimensional substrates by low frequency (50 Hz) plasma chemical vapor deposition method using a TiCl4+N2+H2 mixture at a substrate temperature of 550 °C with a substrate bias circuit using two diodes. The maximum value of the deposition rate was 1200 nm/h at a substrate bias voltage VB of −150 V and the ratio of flow rate k(N2/TiCl4)=2. The maximum value of Vickers hardness of deposited TiN films using Micro–Vickers hardness tester was about 2400 Hv at k=2 and VB=−150 V bias voltage. There were practically no differences between the deposition rates and Vickers hardness on vertical and horizontal substrate surfaces against the surface of electrodes. Resistivity of the films was about 80 μΩ cm at VB from 40 to −150 V with k=2. However, the hardness of deposited film with no substrate bias was about 1000 Hv. This demonstrates the importance of the substrate bias to make uniform and high quality film deposition on three-dimensional substrate surfaces by setting the substrate in the middle of the interelectrode gap. The composition of deposited TiN films was measured by Auger spectra method. It was found that Ti, N, Cl, O, and C were contained in the deposited TiN films. The at. % value of the Cl content [=Cl/(Ti+N+O+C+Cl)] in the TiN films was about 2% with substrate bias voltage, and the ratio of N/Ti was about 1.2.