TISI2 FORMATION AT THE TI-RICH TINX/SI INTERFACE

The thermal stability of TiNx films (0.5≤x≤1.1) and the solid phase reactions in the TiNx/Si system have been studied. The final aim is to form a uniform TiSi2 layer at the interface between TiN and the Si substrate in order to obtain ohmic contact for VLSI metallization by a simple process. TiNx/Si samples with x≥0.9 do not show an apparent structural change by annealing. In sample with 0.5≤x≤0.8, however, the TiNx layer reacts with Si at the interface above 700°C resulting in the formation of TiSi2. At the same time, the TiNx layer with a composition close to the stoichiometric TiN is formed at the film surface. This fact is helpful to obtain the stable TiN/TiSi2/Si contact with low contact resistance not only to n-type, but also to p-type Si, while avoiding contamination at the metal-semiconductor interface. © 1989.