Electrical Contacts and Packaging for Diamond and Diamondlike High-Power Devices

The purpose of this Phase-I SBIR is to demonstrate the feasibility of using filtered cathodic arc deposition (FCAD) to fabricate improved metal multilayer Ohmic and Schottky contacts to CVD diamond. Polycrystalline CVD diamond substrates will be acquired, on which eight Ohmic and two Schottky contact metal multilayer architectures will be fabricated using FCAD. Linear transmission line model (LTLM) and van der Pauw test structures will be photolithographically patterned on Ohmic contacts using standard semiconductor lift off or etch back procedures. These test structures will be used to measure the specific contact resistivity and sheet resistance of Ohmic contacts. The microstructural evolution due to interdiffusion processes, solid-state reactions, and oxidation will be characterized by successive Rutherford backscattering spectroscopy (RBS) and LTLM electrical measurements during thermal aging at 250°C in air for 750 hours. Horizontal Schottky barrier diode (SBD) test structures will be fabricated using FCAD and photolithography, incorporating the best performing Ohmic contact. Current-voltage curves will be measured as a function of temperature, to 250°C, to evaluate the performance of rectifying contacts.