Rapid deposition of polycrystalline diamond film by DC arc plasma jet technique and its RF MESFETs

• 15 × 15 mm2 diamond film is prepared by dc arc plasma jet method.
• IDS of 225.7 mA/mm and fmax of 46.8 GHz are reached.

Diamond is a promising semiconductor material for high power, high frequency and high temperature electronic devices. High-purity polycrystalline diamond with large grain size has showed prominent RF properties. In this work, polycrystalline free-standing diamond film with grain size of 150 μm was grown by DC arc plasma jet technique with a growth speed as high as 20 μm/h. The prepared diamond sample showed high-purity with a (220) preferred orientation by the XRD and Raman spectra measurements. By a self-aligned process, hydrogen terminated p-type diamond MESFETs with gate length of 100 nm were fabricated on the 15 mm × 15 mm diamond film and showed good DC and RF performances with drain saturation current 225.7 mA/mm and maximum oscillation frequency (fmax) 46.8 GHz.