Mechanism of Schottky barrier formation: The role of amphoteric native defects
A correlation between the Fermi level pinning deduced from Schottky barrier heights and from electrical properties of irradiated III--V semiconductors is found. The correlation indicates that similar defects are responsible for the Fermi level stabilization in both cases. It is proposed that amphoteric native defects, i.e., the defects which change their electrical characteristics depending on the Fermi level position, play a dominant role in the processes leading to a Schottky barrier formation. A detailed analysis of metal--GaAs contacts shows that in this case the amphoteric defects responsible for the barrier heights are V/sub Ga/ (acceptor) and a donor complex As/sub Ga/+V/sub As/. It is shown that for thick metal coverages two barriers are formed. A surface barrier determined by the charge associated with a native defect and the bulk barrier controlled by the bulk doping. The sum of the two barrier heights satisfies the Schottky condition for the interface, but it is the bulk barrier that determines the macroscopic electrical properties of the contact. The model explains the evolution of the Fermi level position at the interface observed for metal coverages varying in a broad range of thicknesses. The relationship of the present proposal to previous models of Schottky barriers is discussed.
- Research Organization:
- Center for Advanced Materials, Lawrence Berkely Laboratory, University of California, Berkeley, California 94720
- OSTI ID:
- 6359151
- Journal Information:
- J. Vac. Sci. Technol., B; (United States), Vol. 5:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GALLIUM ARSENIDES
PHYSICAL RADIATION EFFECTS
SCHOTTKY BARRIER DIODES
FABRICATION
CRYSTAL DEFECTS
ELECTRIC CONTACTS
ELECTRICAL PROPERTIES
FERMI LEVEL
VACANCIES
ARSENIC COMPOUNDS
ARSENIDES
CRYSTAL STRUCTURE
ELECTRICAL EQUIPMENT
ENERGY LEVELS
EQUIPMENT
GALLIUM COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
POINT DEFECTS
RADIATION EFFECTS
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
360605* - Materials- Radiation Effects