Low Temperature Deposition and Characterization of N- and P-Type Silicon Carbide Thin Films and Associated Ohmic and Schottky Contacts
Abstract
Monocrystalline silicon carbide (SiC) films have been grown on vicinal 6H-SiC (0001) substrates via gas source molecular beam epitaxy at 1050- 1250 deg C. Using transmission electron microscopy, step bunching was observed at the outset of the initial stage of growth using C3H4/Si2H6 ratios of 1,2 or 10. Subsequent growth occurred via island formation (C2H4-rich) or step-flow (1:1 ratio). Occurrence of the different growth modes may be controlled by changes in the surface diffusion length caused by surface reconstruction as a result of changing the C/Si ratio. Cubic beta-SiC and hexagonal 6H-SiC deposit using high and 1:1 C/Si ratios, respectively. Unintentionally doped films are n- type with n = (0.2-1.0) x 10(exp 17)/cu cm. Similar atomic and hole concentration of 5 x 10(exp 18) and 1.2 x 10 (exp 18), respectively, were measured in Al-doped p-type films. AlN deposited on 6H-SiC (0001) substrates possess a negative electron affinity. The surface Fermi level of the AlN is approx. 3.5 eV above the valence band maximum. Thin film electrical contacts of Co exhibited rectifying behavior with n < 1.06 and a leakage current of 2.0 x 10(exp -8) at -10 V. After annealing at 1000 deg C for 2 min, ohmic-like behavior was observed as a result of significant interface reaction.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1994
- Accession Number
- ADA281060
Entities
People
- Lisa M. Porter
- M. C. Benjamin
- Robert F Davis
- Robert J. Nemanich
- S. Kern
- Shuta Tanaka
Organizations
- North Carolina State University