Structural and electrical characterization of gold/chemically vapor deposited diamond contact

Structural and electrical characteristics of a gold contact to chemically vapor deposited diamond film were investigated. The film was polycrystalline with defective crystals of octahedral morphology, contained nondiamond forms of carbon, silicon, tungsten, and gold, and also incorporated other defects such as vacancies. The silicon/diamond interface contained voids of different sizes. The contact exhibited rectifying characteristics with a breakdown voltage of about 30 V. The ideality factor calculated on the basis of a thermionic emission model is rather large for other mechanisms beside thermionic emission to be operative. Electrical conduction can be explained by the space charge limited current in the presence of exponential trap distribution. The trap distribution is characterized by two different sets of parameters, one at low voltages (up to 4.2 V) and the other at higher voltages (greater than 4.2 V).