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Stabilized Barrier Schottky Diode

IP.com Disclosure Number: IPCOM000060974D
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 87K

Publishing Venue

IBM

Related People

Wagner, LF: AUTHOR

Abstract

A technique is disclosed for improving stability of Schottky barrier diodes (SBDs) by reducing the sensitivity of the barrier height to the electric field through the introduction of impurities near the rectifying interface. The impurities are chosen because of their having acceptor states at the optimum energy. Their effect is to make the ideality factor closer to the ideal state of 1 and reduce reverse bias leakage. The method applies to titanium-tungsten or platinum-silicon diodes on n-type silicon. However an analogous approach may be effected for other anodes, semiconductors, or p-type semiconductors.

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Stabilized Barrier Schottky Diode

A technique is disclosed for improving stability of Schottky barrier diodes (SBDs) by reducing the sensitivity of the barrier height to the electric field through the introduction of impurities near the rectifying interface. The impurities are chosen because of their having acceptor states at the optimum energy. Their effect is to make the ideality factor closer to the ideal state of 1 and reduce reverse bias leakage. The method applies to titanium-tungsten or platinum- silicon diodes on n-type silicon. However an analogous approach may be effected for other anodes, semiconductors, or p-type semiconductors. The barrier height, rB, for an SBD is approximately given by rB = rBF + aE where rBF is the flat band barrier height a is the Andrews-Lepselter proportionality factor E is the electric field (negative for reverse bias) The increase of the negative electric field at small forward and reverse bias lowers the barrier and is responsible for non- ideal forward I-V curves and excess reverse current in the diode. The technique reduces the value of a by increasing the interface state density at the energy in the gap where the barrier is pinned, thus reducing the sensitivity of the barrier height to electric field. This may be accomplished by adding appropriate impurities near the Si surface under the anode or at the anode-silicon interface. These may be introduced by ion implantation, shallow diffusion or mixing with the anode prior to silicide formation or annealing. Selection of the impurity is significant since it should have acceptor levels near or slightly above the pinned position of the anode Fermi energy in t...