Mechanism investigation of NiOx in Au/Ni/p-type GaN ohmic contacts annealed in air

Lee, Ching-Ting; Lin, Yow Jon; Lee, Tsung Hsin

doi:10.1007/s11664-003-0155-6

Cited by 10 publications

(1 citation statement)

References 25 publications

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“…Figure 1 shows a schematic cross section of a GaN HFETs with a p-type material for the gate and a band diagram of various gate materials. [14][15][16] The p-type NiO is a gate material suitable for realizing normally-off operation in GaN HFETs because this material has a wide bandgap of 4 eV and its equivalent work function is as high as those of p-GaN and p-AlGaN, which enable normally-off operation. 11,12) In this lateral device, R on can be effectively reduced by reducing the distance between S=D electrodes.…”

Section: Experimental Methodsmentioning

confidence: 99%

NiO gate GaN-based enhancement-mode hetrojunction field-effect transistor with extremely low on-resistance using metal organic chemical vapor deposition regrown Ge-doped layer

Suzuki

Choe

Yamada

et al. 2016

Jpn. J. Appl. Phys.

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In this paper, we present a normally-off GaN-based transistor with an extremely low on-resistance (R on) fabricated by using a Ge-doped n++-GaN layer for ohmic contacts. We developed a novel GaN regrowth technique using Ge as a dopant, which achieved an extremely high doping concentration of 1 × 1020 cm−3, and thereby the lowest specific contact resistance of 1.5 × 10−6 Ω·cm2. The NiO gate fabricated using an atomic layer deposition technique reduced the spacing between the source and drain electrodes. The fabricated device showed the record-breaking R on of 0.95 Ω·mm with the maximum drain current and transconductance of 1.1 A/mm and 490 mS/mm, respectively. Note that the obtained threshold voltage was 0.55 V. This extremely low R on characteristic indicates the great potential of NiO-gate GaN-based heterojunction field-effect transistors.

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