Accession Number : ADA307091

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 Jan-31 Mar 96,

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 : ADA307091

Report Date : MAR 1996

Pagination or Media Count : 27

Abstract : A CVD system is being fabricated for growth of 4H- and 6H-SiC homoepitaxial thin films. Most system components have been received. The design incorporates a load lock on which the growth and RHEED chambers are attached. The diffusion lengths of the minority carriers in n- and p-type 4H-SiC and 6H-SiC and their variation with T were measured using SEM in the EBIC mode and a Schottky barrier diode structure composed of Ti/Al contacts. The diffusion length for holes (Lp) was approx. equal 0.4 mm in n-type 6H-SiC and Ln was approx. equal 1.2 mm in p-type 6H-SiC. Ln in p-type 4H-SiC was 1.4 mm and Lp, was 0.6 mm in n-type 4H-SiC. Thin layers (2-8 A) of Pt ohmic contact material were deposited on p-type 6H-SiC(0001) surfaces which had and had not been exposed to H. Photoemission measurements indicated the presence of a downward band bending at the surfaces of both samples. Preliminary calculations indicate that the Schottky barrier height of Pt on the H-treated sample was substantially less than that on the non-H-treated sample. A mask set has been designed and received to fabricate MOS capacitors and MOS gated diodes for characterization of the SiO2-SiC interface. Initial experiments indicate that the fabrication steps conform to the requirements of the device process, and the process has been started.

Descriptors :   *SEMICONDUCTOR DEVICES, *ELECTRIC CONTACTS, DIODES, LAYERS, CHARGE CARRIERS, METAL OXIDE SEMICONDUCTORS, IMPURITIES, HYDROGEN, PHOTOELECTRIC EMISSION, SEMICONDUCTOR JUNCTIONS, DIFFUSION, DOPING, SCHOTTKY BARRIER DEVICES, SILICON CARBIDES, MASKS, ELECTRICAL MEASUREMENT.

Subject Categories : Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE