Hirokuni Tokuda

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Hall electron mobility ͑␮ H ͒ and sheet concentration ͑n s ͒ in AlGaN/GaN heterostructures have been measured from 77 to 1020 K. The effect of the deposited Al 2 O 3 layer is also investigated with varying its thickness. It is found that ␮ H decreases monotonously with the temperature ͑T͒ and its dependence is well approximated with the function of ␮ H =(More)
SUMMARY This paper describes high-temperature electron transport properties of AIGaN-channel HEMT fabricated on a free-standing A1N substrate, estimated at temperatures between 25 and 300°C. The AIGaN-channel HEMT exhibited significantly reduced temperature dependence in DC and RF device characteristics, as compared to those for the conventional A1GaN/GaN(More)
This paper describes experimental results on the correlation between current collapse and electroluminescence observed under high drain bias conditions in AlGaN/GaN HEMTs with high breakdown voltages over 1000 V. The electroluminescence characteristics were categorized into 2 groups: one from the drain edge with a strong white-appearance emission and the(More)
We demonstrate an AlN/AlGaN high-electron-mobility transistor (HEMT) fabricated on a free-standing AlN substrate. A metal stack, composed of Zr/Al/Mo/Au, was found to show low contact resistivity for source and drain ohmic contacts. The fabricated AlN/AlGaN HEMT exhibited a maximum drain current of 38 mA/mm with a threshold voltage of-3.4 V. Negligible(More)
The effects of sputtered SiN on current collapse of AlGaN/GaN HEMTs have been studied. The current collapse in terms of dynamic on-state resistance was reduced with increasing SiN deposition and post annealing temperatures due to the reduction of SiN/AlGaN interface trap density. These results indicate that sputtered SiN with deposition temperature at 250(More)
A GaN Schottky diode using Zr/Al/Mo/Au metal stack for Schttky contact has been newly developed. Turn-on (V<inf>on</inf>) and breakdown voltages (V<inf>br</inf>) are controllable with varying the annealing temperature. The fabricated diode shows the values V<inf>on</inf>, series resistance (R<inf>s</inf>), capacitance (C<inf>0</inf>), and V<inf>br</inf> to(More)
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