Ohmic contacts formed by ion mixing in the Si-diamond system

Abstract
Graded-bandgap contacts to natural type-IIb diamond formed by ion-beam mixing of Si (500 Å/diamond samples) are discussed. Ion mixing was carried out using 240-keV Kr+ ionsat a dose of 2×1016/cm2 at a temperature of 700°C. Si-C bonds were observed by IR absorption measurements, indicating the formation of a Si/SiC/diamond graded structure. Transmission line model measurements show that well behaved ohmic contacts can be formed on n-type channels by ion mixing with a subsequent thermal anneal. Samples without ion mixing showed higher specific contact resistivity than ion-mixed samples (~5×10-3 Ω-cm2 versus ~1×10-3 Ω-cm2). For comparison purposes. Au-Ta-based contacts were also prepared