Studies of AlGaN/GaN high-electron-mobility transistors on 4-in. diameter Si and sapphire substrates

S. Arulkumaran, T. Egawa, H. Ishikawa

研究成果: Article査読

40 被引用数 (Scopus)


The AlGaN/GaN high-electron-mobility transistors (HEMTs) fabrication and its dc characteristics have been performed on both 4-in. diameter Si and sapphire substrates. Due to the high crystalline quality with one order low dislocation density of GaN on sapphire substrate, better 2DEG mobility with high values of drain current density (511 mA/mm) and extrinsic transconductance (198 mS/mm) were observed. Large OFF-state breakdown voltage (BVgd) with low gate leakage current was observed on sapphire-based HEMTs. Though the sapphire-based HEMTs show better characteristics than Si-based HEMTs, the thermal dissipation from the device is not good enough. The low thermal resistance of Si-based HEMTs leads the existence of high ON-state BV gd. This has been confirmed by measuring the device surface temperature (TD) by infrared microscope camera. Higher value of TD = 74 °C at VDS = 20 V and VGS = +1.5 V was observed on sapphire-based single finger 400-μm-wide and 2-μm-gate-length HEMTs when compared to the HEMTs on Si (TD = 41 °C). The measured TD has been directly correlated with the measured drain current reduction (IDreduc.) due to self-heating. About 83% of high rate of increase in temperature by self-heating was observed on sapphire-based HEMTs when compared to Si-based HEMTs. The device thermal impedance (Rth) of Si- and sapphire-based AlGaN/GaN HEMTs are 44 and 139 °C/W, respectively. The ratio of RthSi/RthSapp = 0.30 obtained from our studies is consistent with the reported values of 0.297. The 4-in. diameter Si has been shown to be a viable alternative substrate for low-cost high-power operating GaN HEMTs.

ジャーナルSolid-State Electronics
出版ステータスPublished - 2005 10月

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学
  • 電子工学および電気工学
  • 材料化学


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