IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Electronics Tuesday Sessions
       Session EL-TuP

Paper EL-TuP9
Positron Annihilation Studies of Defects at Metal-silicon Carbide Interfaces

Tuesday, October 30, 2001, 5:30 pm, Room 134/135

Session: Electronic Materials Poster Session
Presenter: P.R. Dunstan, University of Wales, UK
Authors: P.R. Dunstan, University of Wales, UK
H.M. Fretwell, University of Wales, UK
D. Jones, University of Wales, UK
S.P. Wilks, University of Wales, UK
M. Charlton, University of Wales, UK
D.P. van der Werf, University of Wales, UK
A. van Veen, Interfaculty Reactor Institute (IRI), Netherlands
H. Schut, Interfaculty Reactor Institute (IRI), Netherlands
Correspondent: Click to Email
Positron annihilation has become an important technique for the investigation of vacancy-like defects. The mechanism for the formation of Ohmic and Schottky metal contacts to silicon carbide is not well understood and positron annihilation spectroscopy studies offer a detailed insight into the role of defects at the interface. Our investigations have concentrated on a number of different preparations, each of which produced different I/V characteristics. Chemical cleaning, ultra-high vacuum preparation and in-situ annealing were all addressed and we demonstrated a significant difference in the Doppler broadened S parameter for each type of contact. In particular the presence of fewer defects at Schottky contacts than at Ohmic contacts was apparent. Temperature studies performed were also able to correlate the reduction of defects with the improvement of Schottky I/V characteristics. The results represent a significantly step in understanding and controlling metal contacts to silicon carbide.