Titanium Germanosilicide Phase Formation During The Ti-Si1-xGex Solid Phase Reactions

Abstract

AbstractThe effect of Si1−xGex alloy composition on the titanium germanosilicide phase formation sequence during the Ti-Si1−xGex solid phase reaction was examined. For the Ti-Si reaction the initial formation of C49 TiSi2 is followed, at higher temperatures, by the formation of C54 TiSi2. For the Ti-Ge reaction the initial formation of Ti6Ge5 is followed, at higher temperatures, by the formation of C54 TiGe2. It was determined that the Ti-Si1−xGex reaction follows three different reaction paths depending on the composition of the initial Si1−xGex alloy. For Si rich Si1−xGex alloys the Ti-Si1−xGex reaction follows a “Ti-Si like” reaction path (Ti+M ↠ C49 TiM2 ↠ C54 TiM2, where M = Si1−xGex). For Ge rich Si1−xGex alloys the reaction follows a “Ti-Ge like” reaction path (Ti+M ↠ Ti6M5 ↠ C54 TiM2). Both Ti6M5 and C49 TiM2 form during the reaction of titanium with Si1−xGex alloys in an intermediate composition range. Properties of the final C54 phase were observed to be strongly dependent on the phase formation sequence. Smooth continuous C54 titanium germanosilicide forms during the “Ti-Si like” reaction and discontinuous islanded C54 titanium germanosilicide forms during the “Ti-Ge like” reaction. An optimum Si1−xGex alloy composition range of 0.00 ≤ x ≤ 0.36 was determined for the formation of continuous- low-resistivity- C54 titanium germanosilicide films from the solid phase reaction of Ti and Si1−xGex alloy.