Abstract
Au-free, Ti/Al/Ta ohmic contact on the AlGaN/AlN/GaN heterostructure using low annealing temperature is studied in this paper. With SiCl4 plasma treatment at the recess-etched contact region, a low contact resistance of 0.52 ω mm and a low sheet resistance of 373 ω/sq are achieved after annealing at 550 °C for 30 s. The low annealing temperature also leads to better surface morphology. Furthermore, AlGaN/AlN/GaN high-electron-mobility transistors (HEMTs) are fabricated with the 550 °C, 30 s annealed Ti/Al/Ta ohmic contacts, and a maximum transconductance of 123 mS/mm and a maximum drain current of 510 mA/mm are obtained for a gate length of 4 μm. Based on Silvaco's Atlas device simulation framework, a scaled-down device with a short gate length of 1 μm would produce a maximum drain current density of 815 mA/mm. It indicates that the direct current performance of the HEMTs with the ohmic metal proposed in this work is considerably better than that with Au-based ohmic contact.
Original language | English (US) |
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Article number | 062206 |
Journal | Journal of Vacuum Science and Technology B |
Volume | 38 |
Issue number | 6 |
DOIs | |
State | Published - Nov 1 2020 |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Instrumentation
- Process Chemistry and Technology
- Surfaces, Coatings and Films
- Electrical and Electronic Engineering
- Materials Chemistry