Enhancement mode metal-semiconductor field effect transistors from thin-film polycrystalline diamond

Polycrystalline CVD diamond films with a near surface hydrogenated layer have been used to form the first normally off enhancement mode MESFET structures from this material. A room temperature transconductance of 0.14 mS/mm has been measured, the highest yet reported for a transistor structure made from polycrystalline material. The devices fully turn off, display saturation and have a low gate leakage current. Al forms a near ideal Schottky barrier on this material (SBH /spl sim/0.98 eV, ideality <1.1) and was used as the gate metallization within the MESFET. Optimized forms of these structures would appear to offer a commercially viable route to high-performance diamond based electronic circuits.