Accession Number : ADA303270

Title :   Defects and Impurities in 4H- and 6H-SiC Homoepitaxial Layers: Identification, Origin, Effect on Properties of Ohmic Contacts and Insulating Layers and Reduction.

Descriptive Note : Quarterly technical rept. 1 Oct-31 Dec 95,

Corporate Author : NORTH CAROLINA STATE UNIV AT RALEIGH

Personal Author(s) : Davis, R. F. ; Aboelfotoh, M. O. ; Baliga, B. J. ; Nemanich, R. J.

PDF Url : ADA303270

Report Date : DEC 1995

Pagination or Media Count : 52

Abstract : The two most important materials related problems affecting the performance of all SiC devices and their associated components (e.g., contacts) are the defects and the undesired impurities which become incorporated in the homoepitaxial SiC layers in which all devices are currently fabricated. Bhatnagar has shown that the reverse blocking leakage current in high voltage Schottky diodes is three orders of magnitude higher than theoretically predicted as a result of defects in the epilayer. The formation of micropipes, stepped screw dislocations, interacting dislocation loops, polyganized networks of dislocations and growth twins as well as stacking faults during the sublimation growth of SiC boules are likely the root cause of some of the defects in the epitaxial layer. However, with the exception of the micropipes, the types and concentrations of line, planar and other three dimensional defects and their effect on the performance of devices and individual device components in the important epilayer have not been simIlarly determined. As such, it is not known which of the latter defects actually are translated from the wafer into the epilayer during its deposition and, therefore, should be vigorously controlled during boule growth and which defects are generated during deposition.

Descriptors :   *SILICON CARBIDES, *ELECTRIC CONTACTS, DIODES, ALUMINUM ALLOYS, LAYERS, CHEMICAL VAPOR DEPOSITION, EPITAXIAL GROWTH, IMPURITIES, DEFECTS(MATERIALS), CONCENTRATION(COMPOSITION), NICKEL ALLOYS, LEAKAGE(ELECTRICAL), SCHOTTKY BARRIER DEVICES, STACKING, HIGH VOLTAGE.

Subject Categories : Electrical and Electronic Equipment
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE