TiN 공정 변수에 따른 MOS Device의 Work Function Modulation

Abstract

TiN thin films were formed by plasma enhanced atomic depostion (PEALD) process using tetrakis(dimethylamino)titanium (TDMAT) and titanium tetrachloride (TiCl4) precursors. By analyzing the process conditions, the behavior and POR conditions of TiN thin film characteristics were obtained. TDMAT precursor based TiN growth rate is 0.96 Å / cycle, and have film density of 4.1 g/cm3 and uniformity: 2.74%. resistivity 196.2 μΩ·cm (Tfilm = 30 nm), roughness 0.3 nm. TiCl4 precursor based TiN thin film obtain properties for using metal electrode, deposition rate 0.63 Å/cycle, resistivity 166 μΩ·cm, roughness 0.3 nm. TiN thin film on this study working by electrode on metal oxide semiconductor (MOS) device and we analysis electrical properties behavior according to process condition variation. In TDMAT based TiN thin films, flat band voltage and effective work function shifted by process condition like process temperature and reactant pulse time. Effective work function could tuning ~ 0.2 eV. With chemical analysis (XPS, EDX), we observed mechanism of effective work function variation by carbon which in TDMAT precursor. In TiCl4 based TiN, only thickness, VFB shift ~280mV. By applying the experimental results from MOS capacitor to the metal oxide semiconductor field effect transistor (MOSFET), we tuning VT about 185mV without degradation of performance, which was also stable in the subsequent thermal process.