The effect of film thickness on the C40 TiSi2 to C54 TiSi 2 transition temperature

Abstract

In this paper, we investigate the transformation of TiSi2 from the high-resistivity C40 phase to the low-resistivity C54 phase. In particular, the effect of C40 film thickness on the transition temperature, which has not been studied in the literature, is scrutinized. Two types of laser, i.e., Nd:YAG (yttrium aluminum garnet) and excimer laser, were used to induce C40 TiSi 2 on samples of 350 Å of Ti deposited on (100) Si substrates. It was also found that the thicker C40 TiSi2 (40 nm) induced by the Nd:YAG laser required a very high temperature of more than 1000°C and an activation energy of 6.5 eV for the formation of the stable C54 TiSi 2, whereas a thinner C40 TiSi2 (15 nm) produced by the excimer laser required a low temperature of 700°C and an activation energy of 2.5 eV to transform into C54 TiSi2. The much lower transition temperature for the thin samples is attributed to the compressive strain in these samples. © 2005 The Electrochemical Society. All rights reserved.