Elimination of carbon vacancies in 4H-SiC employing thermodynamic equilibrium conditions at moderate temperatures

Journal Article · Mon Dec 21 00:00:00 EST 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4938242· OSTI ID:22486269

Ayedh, H. M.; Svensson, B. G. ^[1]; Nipoti, R. ^[2]; Hallén, A. ^[3]

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1. University of Oslo, Department of Physics/Center for Materials Science and Nanotechnology, P.O. Box 1048 Blindern, N-0316 Oslo (Norway)
2. Consiglio Nazionale delle Ricerche, Istituto di Microelettronica e Microsistemi, Sezione di Bologna (CNR-IMM of Bologna), I-40129 Bologna (Italy)
3. Royal Institute of Technology, School of Information and Communication Technology (ICT), SE-164 40 Kista-Stockholm (Sweden)

The carbon vacancy (V{sub C}) is a major point defect in high-purity 4H-SiC epitaxial layers limiting the minority charge carrier lifetime. In layers grown by chemical vapor deposition techniques, the V{sub C} concentration is typically in the range of 10{sup 12 }cm{sup −3}, and after device processing at temperatures approaching 2000 °C, it can be enhanced by several orders of magnitude. In the present study, both as-grown layers and a high-temperature processed one have been annealed at 1500 °C and the V{sub C} concentration is demonstrated to be strongly reduced, exhibiting a value of only a few times 10{sup 11 }cm{sup −3} as determined by deep-level transient spectroscopy measurements. The value is reached already after annealing times on the order of 1 h and is evidenced to reflect thermodynamic equilibrium under C-rich ambient conditions. The physical processes controlling the kinetics for establishment of the V{sub C} equilibrium are estimated to have an activation energy below ∼3 eV and both in-diffusion of carbon interstitials and out-diffusion of V{sub C}'s are discussed as candidates. This concept of V{sub C} elimination is flexible and readily integrated in a materials and device processing sequence.

• OSTI ID: 22486269
• Journal Information: Applied Physics Letters, Vol. 107, Issue 25; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACTIVATION ENERGY
ANNEALING
CARBON
CHARGE CARRIERS
CHEMICAL VAPOR DEPOSITION
DEEP LEVEL TRANSIENT SPECTROSCOPY
DIFFUSION
EPITAXY
EQUILIBRIUM
EV RANGE
IMPURITIES
INTERSTITIALS
LAYERS
PROCESSING
SILICON CARBIDES
TEMPERATURE RANGE 1000-4000 K
VACANCIES