Diamond devices and electrical properties

Abstract

Diamond offers tremendous potential for electronic applications such as field effect transistors. An investigation of the electrical properties of boron-doped homoepitaxial diamond films and the metal-oxide-diamond gate structure was performed. Additionally, field effect transistors were fabricated and characterized. Improvements in the diamond deposition process produced boron-doped homoepitaxial diamond films where the room temperature Hall mobility exceeded 1000 cm2 V−1 s−1. Analysis of the temperature-dependent carrier concentration indicated that the compensation was < 3 × 1015cm−3. The gate structure for metal-silicon dioxide-boron-doped diamond field effect transistors was evaluated by current-voltage and capacitance voltage measurements. Good correlation of the uncompensated acceptor concentration, determined by capacitance-voltage measurements, and the boron concentration, determined by secondary ion mass spectroscopy, was attained. Preliminary measurements suggested that the density of interface states for this structure was ≈ 1012 cm−2 eV−1. Field effect transistors exhibited saturation and pinch-off at temperatures as high as 773 K. The highest normalized transconductance measured was 1.3 mS mm−1. The field effect transistors were combined into analogue and digital circuits that operated at 523 K and 673 K, respectively.