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The Schottky barrier heights of single crystal NiSi(2) on Si (111): The effect of a surface P-N junction.

01 January 1986

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Current-voltage, capacitance-voltage and activation energy measurements obtained on epitaxial nickel silicides grown on Si(111) have exposed the importance of the temperature used to flash evaporate oxide off the surface prior to metal deposition. Near ideal behavior is found for Schottky barriers grown on substrates cleaned at ~820C in ultrahigh vacuum. The Fermi level positions at the interfaces of single crystal type A and type B NiSi(2) are shown to differ by greater than 100 meV. Transmission electron microscopy demonstrated the epitaxial perfection of these silicide layers. At a cleaning temperature of 1050C, the apparent Schottky barrier heights increased substantially for substrates with doping concentration of Nd ~0.75eV) which no longer bears immediate relationship to the interface Fermi level position. Recent discrepancies reported by different groups concerning the barrier heights of NiSi(2) on Si(111) are attributed to this effect.