Low-temperature thin film nitride transformation reactions

This study illustrates a novel method of transforming between two refractory nitride thin films at temperatures well below their respective melting points. Silicon nitride (Si₃N₄) is an excellent thermal and electronic insulator, with applications in the microelectronic, automotive and technical ceramic industries. Thermodynamically, there is a significant decrease in the Gibb´s Free Energy inherent in the transformation between Si₃N₄ and a number of refractory metal nitrides if they are in contact at high temperature; however, these transformation reactions are limited in the pure state by a kinetic barrier at any temperature appreciably lower than the melting point of Si₃N₄ (-2173 K). Previous results presented at this conference illustrated the successful conversion of powdered amorphous Si₃N₄ to TiN. The transformation is made possible by a liquid phase present in a number of Ti-based alloys at temperatures in the vicinity of 800 °C. Current results indicate the full conversion of SiN_x nitride thin films into conducting TiN. Such transformations provide a novel pathway for metallization with a variety of electronic applications.