Correlation of interface chemistry to electrical properties of metal contacts on diamond

• Published in: Diamond and related materials Vol. 2; no. 5; pp. 963 - 969
• Main Authors: Tachibana, T., Glass, J.T.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 13.04.1993
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/0925-9635(93)90259-5

Three different metals (Au, Al and Ti) were deposited on polycrystalline diamond films. The effects of post-deposition annealing and pre-deposition Ar + sputtering were examined. Au and Al did not chemically interact with diamond and formed rectifying contacts on the as-grown surface. The non-reactive interface is an important factor in forming rectifying contacts on diamond. On the contrary, Ti formed a carbide at the interface upon annealing. The resulting contact showed ohmic characteristics. Au was non-reactive even on an Ar +-sputtered diamond surface, while Ti and Al formed carbides on this surface upon annealing at temperatures as low as 430°C. Ti and Al on the sputtered surface resulted in ohmic contacts. Based on these observations, a model of the metal-diamond interface band structure is presented. Combining experimental results with bulk thermodynamic data of carbides has allowed an understanding of the interface chemistry between diamond and various metals.