[15p-4C-1~14] 13.8 Compound and power electron devices and process technology

[15p-4C-3] High Breakdown Voltage AlGaN/GaN HEMTs on Free-Standing GaN Substrate

〇(M1)JIEHONG NG¹, T. Asubar Joel¹, Hirokuni Tokuda¹, Masaaki Kuzuhara¹ (1.Fukui Univ.)

Keywords:AlgaN/GaN HEMT,High Breakdown Voltage,Free-Standing GaN Substrate

In this paper, we have investigated the relationship between off-state breakdown voltage and gate-to-drain distance for AlGaN/gaN HEMTs fabricated on a free-standing semi-insulating GaN substrate.The devices with Al content of 20%, gate length of 3 um and gate-to-drain distance varying from 5 to 200 um were fabricated.Using ICP dry-etching with BCL₃/CL₂, all devices were siolated by a depth of about 250 nm. The off state breakdown voltage exhibited a linear increase up to gate-to-drain distance of around 80 um but saturated at about 4000 V when gate-to-drain distance > 80 um. Almost constant breakdown voltage of around 4000 V was also measured between 2 ohmic contacts separated by mesa isolation with a spacing from 250 to 410 um, indicating that the breakdown voltage of HEMTs in linear region was dominated by leakage current under the channel while that in saturation region was determined by the leakage current outside of the channel.