EP0111706A1
Expired / Lapsed
EP
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Sidewall isolation for gate of field effect transistor and process for the formation thereof
Assignee: International Business Machines Corp
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Filing: 1983-11-03
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Granted: —
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Expires: 2003-11-03
Abstract
Abstract Recesses (13) are formed in the sidewall isolation (7, 8, 9) of the polysilicon gate (6) of a field effect transistor in order that a subsequently deposited metal film becomes discontinuous over the sidewall isolation. The recesses eliminate possible silicon diffusion paths over the sidewall isolation. The sidewall isolation is composed of layers (7, 8, 9) of different insulating materials (eg silicon dioxide (7, 9) and silicond nitride (8)) which can be differentially etched to provide the recesses (13) in the central layer (8).
Inventors
- 👤 Subramanian Srikanteswara Iyer
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 11:15
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/60; H10D64/66; H10D64/671; H10D30/00; H10D30/01; H10D30/021; H10D30/0212; H10D30/0223; H10D64/01; H10D64/021
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
53 words
A field effect transistor structure including a gate (6) provided with first and second layers (7, 8) of insulating materials on its sidewalls, the material of the first layer being different from that of the second layer, characterised by there being a recess (13) formed in one of the first and second layers.
Claim 2
Dependent Claim
53 words
A field effect transistor structure including a gate (6) provided with first and second layers (7, 8) of insulating materials on its sidewalls, the material of the first layer being different from that of the second layer, characterised by there being a recess (13) formed in one of the first and second layers.
Claim 3
Dependent Claim
35 words
A structure as claimed in claim 1, in which there is a third, outer layer of insulating material on the sidewalls of the gate and in which the recess is formed in the second layer.
Claim 4
Dependent Claim
19 words
A structure as claimed in claim 2, in which the first and third layers are of the same material.
Claim 5
Dependent Claim
17 words
A structure as claimed in any preceding claim, in which the first layer is of silicon dioxide.
Claim 6
Dependent Claim
16 words
A structure as claimed in claim 4, in which the second layer is of silicon nitride.
Claim 7
Dependent Claim
17 words
A structure as claimed in any preceding claim, in which the gate is composed of conductive polysilicon.
Claim 8
Dependent Claim
51 words
A process for forming a field effect transistor structure including forming first and second layers of insulating materials on the sidewall of a gate, the material of the first layer being different from that of the second layer, characterised by forming a recess in one of the first and second layers.
Claim 9
Dependent Claim
51 words
A process for forming a field effect transistor structure including forming first and second layers of insulating materials on the sidewall of a gate, the material of the first layer being different from that of the second layer, characterised by forming a recess in one of the first and second layers.
Claim 10
Dependent Claim
40 words
A process as claimed in claim 7, in which the first and second layers are of materials which etch at different rates in a predetermined etchant and the recess is formed by application of the predetermined etchant to the layers.
Claim 11
Dependent Claim
39 words
9 . A process as claimed in claim 7 or claim 8, further including forming a third, outer layer of insulating material on the sidewalls of the gate, and in which the recess is formed in the second layer.
Claim 12
Dependent Claim
19 words
A process as claimed in claim 9, in which the first and third layers are of the same material.
Claim 13
Dependent Claim
20 words
A process as claimed in any of claims 7 to 10, in which the first layer is of silicon dioxide.
Claim 14
Dependent Claim
16 words
A process as claimed in claim 11, in which the second layer is of silicon nitride.
Claim 15
Dependent Claim
54 words
A process as claimed in any of claims 7 to 12, in which the gate electrode is of conductive polysilicon, the process further including depositing a metallic layer over the field effect transistor structure and reacting the metallic layer with the semiconductor material including that of the gate electrode, with which it is contiguous.
Claim 16
Dependent Claim
24 words
A process as claimed in claim 13, in which the metallic layer is of titanium, cobalt, nickel or a metal of the platinum group.
References Cited (Backward Citations)
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