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

Graded-bandgap contacts to natural type-IIb diamond formed by ion-beam mixing of Si (500 AA/diamond samples) are discussed. Ion mixing was carried out using 240-keV Kr/sup +/ ionsat a dose of 2*10/sup 16//cm/sup 2/ at a temperature of 700 degrees 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 ( approximately 5*10/sup -3/ Omega -cm/sup 2/ versus approximately 1*10/sup -3/ Omega -cm/sup 2/). For comparison purposes. Au-Ta-based contacts were also prepared.<
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