Interface formation and electrical properties of a TiNx/SiO2/Si structure for application in gate electrodes

Abstract

In this work, we investigate the interface formation and electrical properties between TiNx and SiO2 for application of a gate electrode as a function of annealing temperature, TA. Auger electron spectroscopy (AES) and four-point probe measurement were performed to measure the chemical composition and sheet resistance, Rs, respectively, of TiNx/SiO2 films. Also, interface formation of TiNx/SiO2 films as a function of annealing temperature was investigated by x-ray photoemission spectroscopy (XPS) depth profiling. X-ray diffraction spectra showed an increase in the crystallinity of TiNx above TA=600 °C. AES and XPS data show that thermal annealing of the sample with TiNx deposited at an Ar/N2 gas flow ratio of 6/1 (QAr/QN2=6/1) above 600 °C increases the oxidation reaction of TiNx layers, resulting in the formation of TiO2 phases. The Rs values increased at elevated annealing temperatures above 600 °C for TiNx deposited with QAr/QN2=6/1, but the Rs values of TiNx deposited at an Ar/N2 gas flow ratio of 6:3 continuously decreased up to TA=800 °C.

Oxygen migration in TiO2-based higher-k gate stacks

“…22 ! SIMS from the TiO 2 -containing gate stack reveals that oxygen atoms diffuse upward and oxidize the poly-Si by showing a peaked oxygen signal at the interface ͓Fig.…”