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

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 nonreactive 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.

Duke Scholars

Author Jeffrey Glass Electrical and Computer Engineering