CA1275332C
Expired / Lapsed
CA
⏱️ 0.0 years remaining
Multilayer contact structure
Assignee: Nortel Networks Ltd
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Filing: 1988-08-10
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Granted: 1990-10-16
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Expires: 2008-08-10
Abstract
Abstract Abstract of the Disclosure MULTILAYER CONTACT STRUCTURE A method for forming a contact structure on a silicon surface comprises forming a TiSi2 layer in intimate contact with the silicon surface and a TiNxOy layer overlying the TiSi2 layer, and forming an Al alloy layer on the TiNxOy layer. The TiSi2 layer provides a good electrical contact to the silicon surface, the Al alloy layer reduces the contact resistance, and the TiNxOy layer provides a diffusion barrier to prevent interaction of the Al alloy and TiSi2 which could degrade the contact. -i-
Inventors
- 👤 Vu Quoc Ho
- 👤 Ping Kung Yang
Bibliographic Details
Application Number
—
Jurisdiction
CA
Data Source
google_patents
Last Synchronized
2026-11-09 04:05
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/032; H10W20/047; H10W20/048; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112; H10P; H10P14/00; H10P14/40; H10P14/418; H10W20/056; H10W20/40; H10W20/41; H10W20/425; H10W20/44; H10W20/4484
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
43 words
A method for forming a contact structure on a silicon surface, the method comprising: forming a TiSi2 layer in intimate contact with the silicon surface and a TiNxOy layer overlying the TiSi2 layer; and forming an Al alloy layer on the TiNxOy layer.
Claim 2
Independent Claim
43 words
A method for forming a contact structure on a silicon surface, the method comprising: forming a TiSi2 layer in intimate contact with the silicon surface and a TiNxOy layer overlying the TiSi2 layer; and forming an Al alloy layer on the TiNxOy layer.
Claim 3
Dependent Claim
114 words
A method as defined in claim 1, comprising forming the TiSi2 layer and the TiNxOy layer by: depositing a first Ti layer on the silicon surface; heating the first Ti layer in an O2-depleted N2 ambient to cause Ti adjacent to the silicon surface to react with silicon at the surface to form TiSi2 and to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy overlying the TiSi2; depositing a second Ti layer on the TiNxOy; and heating the second Ti layer in an O2-depleted N2 ambient to cause exposed Ti to react with N2 and any residual O2 to form a further TiNxOy layer overlying the existing TiNxOy.
Claim 4
Dependent Claim
90 words
A method as defined in claim 2, comprising; depositing the first Ti layer to a thickness between 100 angstroms and 1000 angstroms; and heating the first Ti layer in an O2-depleted N2 ambient to a temperature between 600 degrees Celsius and 1100 degrees Celsius for a duration between 2 seconds and 100 seconds to cause Ti adjacent to the silicon surface to react with silicon at the surface to form TiSi2 and to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy overlying the TiSi2.
Claim 5
Dependent Claim
73 words
A method as defined in claim 2, comprising: depositing the second Ti layer to a thickness between 100 angstroms and 1000 angstroms; and heating the second Ti layer in an O2-depleted N2 ambient to a temperature between 600 degrees Celsius and 1100 degrees Celsius for a duration between 2 seconds and 100 seconds to cause exposed Ti to react with N2 and any residual O2 to form additional TiNxOy overlying the existing TiNxOy.
Claim 6
Dependent Claim
117 words
A method as defined in claim 1, comprising forming the TiSi2 layer and the TiNxOy layer by: depositing a first Ti layer on the silicon surface; heating the first Ti layer in an O2-depleted N2 ambient to cause Ti adjacent to the silicon surface to react with silicon at the surface to form TiSi2 and to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy overlying the TiSi2; removing the TiNxOy to expose the TiSi2; depositing a second Ti layer on the TiSi2; and heating the second Ti layer in an O2-depleted N2 ambient to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy overlying the TiSi2.
Claim 7
Dependent Claim
91 words
A method as defined in claim 5, comprising: depositing the first Ti layer to a thickness of between 100 angstroms and 1000 angstroms; and heating the first Ti layer in an O2-depleted N2 ambient to a temperature between 600 degrees Celsius and 800 degrees Celsius for a duration between 2 seconds and 100 seconds to cause Ti adjacent to the silicon surface to react with silicon at the surface to form TiSi2 and to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy overlying the TiSi2.
Claim 8
Dependent Claim
48 words
A method as defined in claim 6, further comprising heating the TiSi2 to a temperature between 600 degrees Celsius and 1100 degrees Celsius for a duration between 2 seconds and 100 seconds to consolidate the TiSi2 after removing the TiNxOy and before depositing the second layer of Ti.
Claim 9
Dependent Claim
68 words
A method as defined in claim 5, comprising: depositing the second Ti layer to a thickness between 100 angstroms and 1000 angstroms; and heating the second Ti layer in an O2-depleted N2 ambient to a temperature between 600 degrees Celsius and 1100 degrees Celsius for a duration between 2 seconds and 100 seconds to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy.
Claim 10
Dependent Claim
27 words
A method as defined in claim 5, comprising removing TiNxOy to expose the TiSi2 by selectively etching the TiNxOy in a mixture of NH4OH, H2O2 and H2O.
Claim 11
Dependent Claim
63 words
A method as defined in claim 1, comprising forming the TiSi2 layer and the TiNxOy layer by: forming a TiSi2 layer in intimate contact with the silicon surface; depositing a Ti layer on the TiSi2; and heating the Ti layer in an O2-depleted N2 ambient to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy overlying the TiSi2.
Claim 12
Dependent Claim
66 words
A method as defined in claim 10, comprising: depositing the Ti layer to a thickness between 100 angstroms and 1000 angstroms; and heating the Ti layer in an O2-depleted N2 ambient to a temperature between 600 degrees Celsius and 1100 degrees Celsius for a duration between 2 seconds and 100 seconds to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy.
Claim 13
Dependent Claim
23 words
A method as defined in claim 1, further comprising sintering the Al alloy layer in H2 at 450 degrees Celsius for 30 minutes.
Claim 14
Dependent Claim
29 words
A method as defined in claim 1, comprising forming on the TiNxOy layer a layer of an Al alloy selected from the group consisting of Al-Si, Al-Cu and Al-Ti.
Claim 15
Independent Claim
177 words
A method for forming a contact structure on a silicon surface, the method comprising: sputter depositing a first Ti layer to a thickness of between 100 angstroms and 1000 angstroms on the silicon surface; heating the first Ti layer in an O2-depleted N2 ambient to a temperature between 600 degrees Celsius and 1100 degrees Celsius for a duration between 2 seconds and 100 seconds to cause Ti adjacent to the silicon surface to react with silicon at the surface to form TiSi2 and to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy overlying the TiSi2; sputter depositing a second Ti layer to a thickness between 100 angstroms and 1000 angstroms on the TiNxOy; heating the second Ti layer in an O2-depleted N2 ambient to a temperature between 600 and 1100 degrees Celsius for a duration between 2 seconds and 100 seconds to cause exposed Ti to react with N2 and any residual O2 to form additional TiNxOy overlying the existing TiNxOy; and forming an Al alloy layer on the TiNxOy layer.
Claim 16
Independent Claim
177 words
A method for forming a contact structure on a silicon surface, the method comprising: sputter depositing a first Ti layer to a thickness of between 100 angstroms and 1000 angstroms on the silicon surface; heating the first Ti layer in an O2-depleted N2 ambient to a temperature between 600 degrees Celsius and 1100 degrees Celsius for a duration between 2 seconds and 100 seconds to cause Ti adjacent to the silicon surface to react with silicon at the surface to form TiSi2 and to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy overlying the TiSi2; sputter depositing a second Ti layer to a thickness between 100 angstroms and 1000 angstroms on the TiNxOy; heating the second Ti layer in an O2-depleted N2 ambient to a temperature between 600 and 1100 degrees Celsius for a duration between 2 seconds and 100 seconds to cause exposed Ti to react with N2 and any residual O2 to form additional TiNxOy overlying the existing TiNxOy; and forming an Al alloy layer on the TiNxOy layer.
Claim 17
Independent Claim
183 words
A method for forming a contact structure on a silicon surface, the method comprising: sputter depositing a first Ti layer to a thickness between 100 angstroms and 1000 angstroms on the silicon surface; heating the first Ti layer in an O2-depleted N2 ambient to a temperature between 600 degrees Celsius and 800 degrees Celsius for a duration between 2 seconds and 100 seconds to cause Ti adjacent to the silicon surface to react with silicon at the surface to form TiSi2 and to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy overlying the TiSi2; removing TiNxOy to expose the TiSi2; sputter depositing a second Ti layer to a thickness between 100 angstroms and 1000 angstroms on the TiSi2; and heating the second Ti layer in an O2-depleted N2 ambient to a temperature between 600 degrees Celsius and 1100 degrees Celsius for a duration between 2 seconds and 100 seconds to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy overlying the TiSi2; and forming an Al alloy layer on the TiNxOy layer.
Claim 18
Independent Claim
183 words
A method for forming a contact structure on a silicon surface, the method comprising: sputter depositing a first Ti layer to a thickness between 100 angstroms and 1000 angstroms on the silicon surface; heating the first Ti layer in an O2-depleted N2 ambient to a temperature between 600 degrees Celsius and 800 degrees Celsius for a duration between 2 seconds and 100 seconds to cause Ti adjacent to the silicon surface to react with silicon at the surface to form TiSi2 and to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy overlying the TiSi2; removing TiNxOy to expose the TiSi2; sputter depositing a second Ti layer to a thickness between 100 angstroms and 1000 angstroms on the TiSi2; and heating the second Ti layer in an O2-depleted N2 ambient to a temperature between 600 degrees Celsius and 1100 degrees Celsius for a duration between 2 seconds and 100 seconds to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy overlying the TiSi2; and forming an Al alloy layer on the TiNxOy layer.
Claim 19
Dependent Claim
49 words
A method as defined in claim 15, further comprising heating the TiSi2 to a temperature between 600 degrees Celsius and 1100 degrees Celsius for a duration between 2 seconds and 100 seconds to consolidate the TiSi2 after removing the unreacted Ti and before depositing the second layer of Ti.
Claim 20
Independent Claim
100 words
A method for forming a contact structure on a silicon surface, the method comprising: forming a TiSi2 layer in intimate contact with the silicon surface: sputter depositing a Ti layer to a thickness between 100 angstroms and 1000 angstroms on the TiSi2; and heating the Ti layer in an O2-depleted N2 ambient to a temperature between 600 degrees Celsius and 1100 degrees Celsius for a duration between 2 seconds and 100 seconds to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy overlying the TiSi2; and forming an Al alloy layer on the TiNxOy layer.
Claim 21
Independent Claim
100 words
A method for forming a contact structure on a silicon surface, the method comprising: forming a TiSi2 layer in intimate contact with the silicon surface: sputter depositing a Ti layer to a thickness between 100 angstroms and 1000 angstroms on the TiSi2; and heating the Ti layer in an O2-depleted N2 ambient to a temperature between 600 degrees Celsius and 1100 degrees Celsius for a duration between 2 seconds and 100 seconds to cause exposed Ti to react with N2 and any residual O2 to form TiNxOy overlying the TiSi2; and forming an Al alloy layer on the TiNxOy layer.
Claim 22
Dependent Claim
42 words
A multilayer contact structure for making electrical contact to a silicon surface, the contact structure comprising: a TiSi2 layer in intimate contact with the silicon surface; a TiNxOy layer on the TiSi2 layer: and an Al alloy layer on the TiNxOy layer.
Claim 23
Dependent Claim
42 words
A multilayer contact structure for making electrical contact to a silicon surface, the contact structure comprising: a TiSi2 layer in intimate contact with the silicon surface; a TiNxOy layer on the TiSi2 layer: and an Al alloy layer on the TiNxOy layer.
Claim 24
Dependent Claim
20 words
A contact structure as defined in claim 18, wherein the TiNxOy layer is approximately 10% O and approximately 50% N.
Claim 25
Dependent Claim
28 words
A contact structure as defined in claim 18, wherein the Al alloy of the Al alloy layer is selected from the group consisting of Al-Si, Al-Cu and Al-Ti.
References Cited (Backward Citations)
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