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US6316357B1
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Method for forming metal silicide by laser irradiation
Assignee: Industrial Technology Research Institute
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Filing: 1997-10-08
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Granted: 2001-11-13
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Expires: 2017-10-08
Abstract
Abstract The present invention discloses a method for forming metal silicide on an electronic structure by first depositing a metal layer on top of a silicon layer of polysilicon, single crystal silicon or amorphous silicon capable of forming a metal silicide, and then irradiating the metal layer with laser energy for a sufficient length of time such that a layer of metal silicide is formed at the metal interface with polysilicon, single crystal silicon and amorphous silicon. The unreacted metal layer on the metal silicide is then removed by a wet dipping method by selecting a suitable etchant for the metal. The present invention novel method can be applied to various metallic materials such as Ti, Co, W, Pt, Hf, Ta, Mo, Pd and Cr. The laser source utilized is a pulse Excimer laser of XeCl, ArF or XeF.
Inventors
- 👤 Kang-Cheng Lin
- 👤 Hong-Woei Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:04
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0212; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112; H10D64/60; H10D64/66; H10D64/661; H10D64/662; H10D64/663; H10P; H10P34/00; H10P34/40; H10P34/42
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
92 words
A method for forming metal silicide on an amorphous silicon surface comprising the steps of: providing an electronic structure having a silicon layer on top, said silicon layer being formed of an amorphous silicon, depositing a metal layer capable of forming a metal silicide on top of the silicon layer forming a metal/silicon interface, irradiating the metal layer with laser energy for a sufficient length of time such that a layer of metal silicide of less than 50 Å thick is formed at the metal/silicon interface, and removing the unreacted metal layer.
Claim 2
Independent Claim
92 words
A method for forming metal silicide on an amorphous silicon surface comprising the steps of: providing an electronic structure having a silicon layer on top, said silicon layer being formed of an amorphous silicon, depositing a metal layer capable of forming a metal silicide on top of the silicon layer forming a metal/silicon interface, irradiating the metal layer with laser energy for a sufficient length of time such that a layer of metal silicide of less than 50 Å thick is formed at the metal/silicon interface, and removing the unreacted metal layer.
Claim 3
Dependent Claim
23 words
A method according to claim 1 , wherein said electronic structure is a ceramic substrate having an amorphous silicon layer deposited on top.
Claim 4
Dependent Claim
23 words
A method according to claim 1 , wherein said electronic structure is a silicon substrate having a layer of polysilicon deposited on top.
Claim 5
Dependent Claim
31 words
A method according to claim 1 , wherein said metal layer is deposited of a material selected from the group consisting of Co, Cr, Ta, Ti, W, Pd, Hf and Mo.
Claim 6
Dependent Claim
25 words
A method according to claim 1 , wherein said metal layer is deposited to a thickness of between about 50 Å and about 1,000 Å.
Claim 7
Dependent Claim
26 words
A method according to claim 1 , wherein said metal layer is preferably deposited to a thickness of between about 300 Å and about 700 Å.
Claim 8
Dependent Claim
26 words
A method according to claim 1 wherein said metal layer is more preferably deposited to a thickness of between about 450 Å and about 550 Å.
Claim 9
Dependent Claim
17 words
A method according to claim 1 , wherein said pre-processed electronic structure is a self-aligned MOSFET device.
Claim 10
Dependent Claim
23 words
A method according to claim 1 , wherein said metal silicide formed has a thickness between about 10 Å and about 100 Å.
Claim 11
Dependent Claim
22 words
A method according to claim 1 , wherein said laser energy is supplied from a Excimer laser operated in a pulse mode.
Claim 12
Dependent Claim
28 words
A method according to claim 10 , wherein said Excimer laser is selected from the group consisting of a XeCl laser, a ArF laser and a XeF laser.
Claim 13
Dependent Claim
24 words
A method according to claim 10 , wherein said Excimer laser operates in a wavelength range between about 220 nm and about 320 nm.
Claim 14
Dependent Claim
25 words
A method according to claim 1 , wherein said sufficient length of time for laser irradiation is between about 5 ns and about 200 ns.
Claim 15
Dependent Claim
26 words
A method according to claim 1 , wherein said sufficient length of time for laser irradiation is preferably between about 30 ns and about 100 ns.
Claim 16
Dependent Claim
19 words
A method according to claim 1 , wherein said unreacted metal layer is removed by a wet dipping method.
Claim 17
Dependent Claim
25 words
A method according to claim 15 , wherein said wet dipping method utilizes an aqueous solution of Ce(No 3 ) 2 and HNO 3 .
Claim 18
Independent Claim
90 words
A method for forming a metal suicide layer on a thin film transistor (TFT) structure comprising the steps of: providing a ceramic substrate having an amorphous silicon layer deposited on top, depositing a metal layer capable of forming a metal silicide on top of the amorphous silicon layer forming a metal/amorphous silicon interface, irradiating the metal layer with laser energy in a pulse mode for a multiple number of times sufficient to form a layer of metal silicide at the metal/amorphous silicon interface, and etching away the unreacted metal layer.
Claim 19
Independent Claim
90 words
A method for forming a metal suicide layer on a thin film transistor (TFT) structure comprising the steps of: providing a ceramic substrate having an amorphous silicon layer deposited on top, depositing a metal layer capable of forming a metal silicide on top of the amorphous silicon layer forming a metal/amorphous silicon interface, irradiating the metal layer with laser energy in a pulse mode for a multiple number of times sufficient to form a layer of metal silicide at the metal/amorphous silicon interface, and etching away the unreacted metal layer.
Claim 20
Dependent Claim
42 words
A method according to claim 17 , wherein said metal layer is deposited of a material selected from the group consisting of Co, Cr, Ta, Ti, W, Pd, Hf and Mo, and to a thickness between about 50Å and about 1000 Å.
Claim 21
Dependent Claim
28 words
A method according to claim 17 , wherein the laser energy is supplied by an Excimer laser of a XeCl laser, an ArF laser or a XeF laser.
Claim 22
Dependent Claim
36 words
A method according to claim 17 , wherein a cooling period is provided between said multiple number of times the metal layer is exposed to the laser energy such that overheating of the substrate is avoided.
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