Study on the transition temperature and phase formation sequence in TiZr silicides on Si(100)

Abstract

We studied the (Ti1−xZrx) silicides with various Zr atomic compositions (x=0.1, 0.3, 0.6). The effects of Zr contents on the transition (C49→C54) temperature, phase sequence, and suppression of agglomeration in TiZr alloy silicide were investigated. We codeposited the Ti and Zr films of 40 nm thickness with an e-beam evaporator in high vacuum and annealed ex situ at temperatures between 600 and 900 °C in 100 °C increments. The phase identification of TiZr silicides was carried out by x-ray diffraction (XRD) and the chemical analysis by Auger electron spectroscopy. The interface morphologies and electrical properties were investigated by the cross-sectional transmission electron microscopy and four-point probe, respectively. The increase in transition temperature was observed with increasing Zr content. TiZr alloy monosilicide was detected by XRD in the Zr composition of 60% of (TiZr) silicide at temperatures below 700 °C and finally transformed to C49 (TiZr) disilicide at temperatures above 800 °C. The interface and surface roughnesses were improved with increasing Zr content and, consistently, the resistivity of TiZr alloy silicide was decreased to μΩ due to the silicide formation and the suppression of silicide agglomeration.