Au-free low-temperature ohmic contacts for AlGaN/AlN/GaN heterostructures
We report 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.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States). Center for Nanoscale Materials (CNM)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); NXP Semiconductors
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1774539
- Alternate ID(s):
- OSTI ID: 1671144
- Journal Information:
- Journal of Vacuum Science and Technology B, Vol. 38, Issue 6; ISSN 2166-2746
- Publisher:
- American Vacuum Society / AIPCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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