High-quality homoepitaxial diamond (100) films grown under high-rate growth condition

We present advantages of high-power microwave plasma chemical vapor deposition (MPCVD) in homoepitaxial diamond film deposition. Diamond films grown at comparatively high growth rate of 3.5 μm/h showed intense free-exciton recombination emission at room temperature. The free-exciton decay time of the diamond film at room temperature, 22 ns, was much longer than that of type-IIa single crystal, indicating electronically high quality of the homoepitaxial films. Dislocation-related emissions were locally observed, a part of which created by mechanical polishing process was successfully removed by surface etching process using oxygen plasma. Another advantage of the high-power MPCVD is effective impurity doping; boron-doped diamond films with high carrier mobility and high carrier concentration were reproducibly deposited. An ultraviolet photodetector fabricated using the high-quality undoped diamond film showed lower noise equivalent power as well as higher photoresponsivity for ultraviolet light with better visible-blind property, compared to those of standard Si-based photodetectors. The high-power MPCVD is, thus, indispensable technique for depositing high quality diamond films for electronic devices.