Low Temperature Deposition and Characterization of N- and P-Type Silicon Carbide Thin Films and Associated Ohmic and Schottky Contacts
Abstract
Gas-source MBE growth of epitaxial layers of 3C (beta)-SiC (1 1 1) on Si faces of 6H-SiC (0001) cut 3 deg -4 deg towards 1120 has been achieved at 1000-1250 deg C using C2H4 and Si2H6. The occurrence of 3C-SiC is attributed mainly to the lower surface mobility of the adsorbed species at the temperatures used in this research. Plan-view TEM and RHEED analysis showed a double positioning structure. This combination of high flow (total flow 2.5 sccm) and low temperatures (1050 deg C) resulted in a very high nucleation density which likely allowed interaction between nuclei very early in growth, leading to a smooth growth surface. Solid solutions and multilayers of AIN and SiC have been grown on 6H-SiC (0001) substrates cut 3 deg -4 deg off-axis to 1120. Evidence is presented which suggests that the AIN-rich solid solutions are cubic. Multilayer structures of 6H-SiC, 2H-AIN, and 3C-SiC were also fabricated. Finally, studies to understand what controls contact electrical characteristics of specific metals to n-type 6H-SiC has continued in order to select the best ohmic and rectifying contacts. Current-voltage measurements have shown that Ti, Pt, and Hf contacts deposited at room temperature on n-type, (0001) 6H-SiC are rectifying, all with ideality factors between 1.01 and 1.09. The lowest leakage currents (- 5 x 10-8 A/cm(2) at -10 V) were found for unannealed Pt contacts and for Hf contacts annealed at 700 deg for 20 minutes.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1992
- Accession Number
- ADA252363
Entities
People
- Robert F Davis
Organizations
- North Carolina State University