THE OXIDATION OF TITANIUM SILICIDE

This paper investigates the morphology changes that occur with the oxidation of a titanium silicide-polysilicon system. These changes were studied as a function of polysilicon doping and silicide formation parameters. Emphasis was placed on transmission electron microscopy studies of the samples by planar and cross sectional techniques. Various surface analysis methods have also been used to characterize the films. This study helps to define the possible use and shortcomings of a self aligned titanium silicide insulator. The results show that varying quality insulators result, dependent largely on the initial conditions of the titanium silicide. After oxidation the Auger and TEM analysis show that in all cases some form of silicon dioxide was created, but typically a considerable amount of titanium oxide was also present. For instance, it was apparent that more titanium oxide formed on the samples RTA'ed for 1 min at 700-degrees-C than the 5 min at 800-degrees-C and considerably more on the arsenic doped sample than the boron doped. The silicide also had morphology changes as the result of the oxidation. There was a phase change from the C49 to C54 phase for the 1 min at 700-degrees-C samples as would be expected at the time and temperature of the oxidation. There also was a significant amount of agglomeration and epitaxial growth observed. Further work is required to completely characterize these phenomena.