Method of forming metal-disilicide layers and contacts
First Claim
1. A method of forming a cobalt-disilicide layer, comprising the steps of:
- providing a silicon-on-insulator substrate having an insulating underlayer and a silicon outerlayer thereon;
forming a first capping layer containing cobalt on said silicon outerlayer;
annealing said substrate to convert a first portion of said silicon outerlayer to a first cobalt-disilicide layer;
forming a second capping layer containing cobalt-silicide on said first cobalt-disilicide layer; and
annealing said substrate to convert a second portion of said silicon outerlayer, between said first portion and said insulating underlayer, to a second cobalt-disilicide layer.
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Accused Products
Abstract
A method of forming a metal-disilicide (MSi2) film from a silicon-on-insulator (SOI) substrate having an insulating underlayer and a silicon outerlayer includes the formation of a first capping layer on a portion of the silicon outerlayer. The first capping layer preferably includes titanium and a preselected metal (M) such as cobalt. A step is then performed to convert a first portion of the silicon outerlayer to metal-disilicide. This step is preferably accomplished by a rapid thermal annealing step. Thereafter, a second capping layer is formed on the metal-disilicide layer. The second capping layer preferably includes titanium and metal-monosilicide (MSi). Next, a step is performed to convert a second portion of the silicon outerlayer, beneath the first portion, to metal-disilicide while preventing phase-reversal of the already formed metal-disilicide layer to metal-monosilicide. This step is preferably accomplished by a rapid thermal annealing step as well. The method can preferably be used to form low resistance metal-disilicide contacts to active regions of SOI electronic devices.
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Citations
24 Claims
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1. A method of forming a cobalt-disilicide layer, comprising the steps of:
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providing a silicon-on-insulator substrate having an insulating underlayer and a silicon outerlayer thereon; forming a first capping layer containing cobalt on said silicon outerlayer; annealing said substrate to convert a first portion of said silicon outerlayer to a first cobalt-disilicide layer; forming a second capping layer containing cobalt-silicide on said first cobalt-disilicide layer; and annealing said substrate to convert a second portion of said silicon outerlayer, between said first portion and said insulating underlayer, to a second cobalt-disilicide layer. - View Dependent Claims (2, 3, 4, 5)
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6. A method of selectively forming a metal-disilicide layer containing silicon and a metal, comprising the steps of:
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forming a first capping layer containing the metal on a silicon substrate; annealing said substrate at a first temperature to convert a first portion thereof to a first metal-disilicide layer containing the metal; and forming a second metal-disilicide layer containing the metal adjacent said first metal-disilicide layer, wherein the metal is selected so that at the first temperature, a Gibbs free energy reduction in forming metal-monosilicide from silicon and the metal is greater than 0.5 times a Gibbs free energy reduction in forming metal-disilicide from silicon and the metal. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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13. A method of forming a silicon-on-insulator insulated-gate field effect transistor having cobalt-disilicide source and drain contacts, comprising the steps of:
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providing a silicon-on-insulator substrate having an insulating underlayer and a silicon outerlayer thereon; forming a gate insulating layer on said silicon outerlayer; forming a conductive gate electrode having first and second ends on said gate insulating layer; forming a source region and a drain region in said silicon outerlayer adjacent the first end and the second end, respectively, of said conductive gate electrode, to thereby define a silicon channel region between said source region and said drain region and between said insulating underlayer and said gate insulating layer; forming insulating spacers on said source and drain regions at the first and second ends of said conductive gate electrode, respectively; forming a first bimetallic capping layer containing cobalt on said source region and on said drain region; and annealing said substrate to convert a first portion of said source region to cobalt-disilicide and covert a first portion of said drain region to cobalt-disilicide. - View Dependent Claims (14, 15, 16, 17, 18, 22, 23, 24)
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19. A method of forming a SOI electronic device having cobalt-disilicide contacts, comprising the steps of:
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providing a silicon-on-insulator substrate having an insulating underlayer and a silicon outerlayer thereon; forming an electronic device having a plurality of active regions in said silicon outerlayer; and forming a cobalt-disilicide contact to at least one of said active regions by; forming a first bimetallic capping layer containing cobalt on said active region; annealing said substrate to convert a first portion of said active region to cobalt-disilicide; forming a second bimetallic capping layer containing cobalt-silicide on said first portion; and annealing said substrate to convert a second portion of said active region, between said first portion and said insulating underlayer, to cobalt-disilicide. - View Dependent Claims (20, 21)
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Specification