[18p-N302-1~18] 13.7 Compound and power electron devices and process technology

△ [18p-N302-17] Current status of evaluation for Radio-Frequency performance in 2DHG Diamond MOSFETs; Output Power Density P_out = 3.8 W/mm at 1 GHz

〇(M1)Ken Kudara¹, Shoichiro Imanishi¹, Kiyotaka Horikawa¹, Atsushi Hiraiwa¹, Hiroshi Kawarada^1,2 (1.Waseda Univ., 2.Waseda ZAIKEN)

Keywords:diamond, Radio frequency, FET

Radio-Frequency (RF) output power of transistor is improved by applying high voltage. We have reported high breakdown voltage diamond FETs exceeding 1500V with 200 nm atomic-layer-deposition (ALD)-Al₂O₃ film. In this work, RF devices are applied based on this high breakdown voltage structure. 2DHG diamond MOSFETs with 100 and 200 nm Al₂O₃ were fabricated on II-a polycrystalline diamond substrate which has high crystallinity, (110) preferential orientation and grain size of approximately 300 μm. At 100 nm thick Al₂O₃ diamond MOSFETs, the maximum P_out of 3.8 W/mm was obtained at high V_DS = −50 V. It is the highest value in diamond FETs. At 200 nm thick Al₂O₃ diamond MOSFET, the P_out of 2.5 W/mm and maximum power gain of 8.0 dB were obtained at V_GS = 16 V andV_DS = −70 V for L_GD = 4.5 μm. The large-signal RF performance was evaluated at V_DS = −70 V for the first time in diamond. We propose diamond as a promising material for radio frequency and high power devices next to GaN.