Interface structure and electronic properties of the titanium-silicon system

Although Schottky barrier diodes and ohmic contacts are used extensively in integrated circuits, no theory currently exists that accurately predicts the electronic properties of the barrier from basic materials parameters. The importance of the metal-silicon interface in determining these properties and the complexity of the reactions observed have made the formulation of such a theory quite difficult. Silicon Schottky barriers were examined by a carefully controlled study of both interface structure and electrical properties for titanium-silicon diodes, which are of interest for use in advanced integrated circuits. An ultra-high vacuum system capable of in situ analysis of interface structure using surface spectroscopies was designed and constructed, and measurement of barrier height was performed using the photoresponse technique. This system provides a well controlled environment, which reduces the confounding effects of uncharacterized contamination, and allows detailed interface studies not otherwise possible. The results impact on both Schottky barrier technology, by elucidating interfacial reactions and correlating them to electrical behavior for relevant systems, and Schottky barrier theory, by determining barrier characteristics that Schottky models must be able to explain.