Height-selective etching for regrowth of self-aligned contacts using MBE

• Published in: Journal of crystal growth 2009-03, Vol.311 (7), p.1984-1987
• Main Authors: Burek, G.J., Wistey, M.A., Singisetti, U., Nelson, A., Thibeault, B.J., Bank, S.R., Rodwell, M.J.W., Gossard, A.C.
• Format: Article
• Language: English
• Subjects: A1. Etching; A1. Nanostructures; A3. Molecular beam epitaxy; A3. Selective deposition; Applied sciences; B2. Semiconducting III–V materials; B3. Field effect transistors; B3. Heterojunction semiconductor devices; Cross-disciplinary physics: materials science; rheology; Electronics; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Transistors
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2008.11.012

Advanced III–V transistors require unprecedented low-resistance contacts in order to simultaneously scale bandwidth, f max and f t with the physical active region [M.J.W. Rodwell, M. Le, B. Brar, in: Proceedings of the IEEE, 96, 2008, p. 748]. Low-resistance contacts have been previously demonstrated using molecular beam epitaxy (MBE), which provides active doping above 4×10 19 cm −3 and permits in-situ metal deposition for the lowest resistances [U. Singisetti, M.A. Wistey, J.D. Zimmerman, B.J. Thibeault, M.J.W. Rodwell, A.C. Gossard, S.R. Bank, Appl. Phys. Lett., submitted]. But MBE is a blanket deposition technique, and applying MBE regrowth to deep-submicron lateral device dimensions is difficult even with advanced lithography techniques. We present a simple method for selectively etching undesired regrowth from the gate or mesa of a III–V MOSFET or laser, resulting in self-aligned source/drain contacts regardless of the device dimensions. This turns MBE into an effectively selective area growth technique.