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Formation of a Transition Metal Schottky Diode by Ion Beam Mixing

IP.com Disclosure Number: IPCOM000052172D
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Campbell, DR: AUTHOR [+2]

Abstract

Transition metal/silicon Schottky diodes are typically processed at temperatures which are too low to create an interfacial metal silicide layer by ordinary equilibrium reaction kinetics. Consequently, the device properties are surface sensitive and difficult to control. Ion-beam mixing can cause the formation of a metal silicide layer at low temperatures, thus producing a stable and reproducible device.

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Formation of a Transition Metal Schottky Diode by Ion Beam Mixing

Transition metal/silicon Schottky diodes are typically processed at temperatures which are too low to create an interfacial metal silicide layer by ordinary equilibrium reaction kinetics. Consequently, the device properties are surface sensitive and difficult to control. Ion-beam mixing can cause the formation of a metal silicide layer at low temperatures, thus producing a stable and reproducible device.

Ion-beam mixing occurs as a result of dynamic collision cascades caused by an implanted primary ion. Provided that the primary ions penetrate to the interface and a little beyond, an interfacial zone of mixed metal and silicon will form between them a metal/silicon couple. For many metals this can result in the formation of a metal silicide compound if a suitable phase exists. Some heating at moderate temperatures during or after implantation may be necessary to complete the compound-forming process, but in any case the temperatures are lower than those needed to react unimplanted layers. Advantage is taken of a higher diffusivity occurring in the implant-damaged regions. The method can be applied to metal alloy films where some selectivity as to the composition and the mixed phase may be obtained by matching the numbers of the implanted ions to one or the other of the alloy constituents.

Schottky diodes made from refractory metals and alloys such as Ta and TiW, respectively, can be improved in ter...