Patent EP0459836A2 successfully refreshed from Google Patents.
EP0459836A2
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Method for fabricating thin-film transistors
Assignee: Semiconductor Energy Laboratory Co Ltd
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Filing: 1991-06-03
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Granted: —
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Expires: 2011-06-03
Abstract
Abstract A process for fabricating thin film transistors (TFTs) which comprises a two-step laser annealing process in which crystallization of the channel portion of a TFT is effected by irradiating the channel portion with an irradiation beam, for example from an excimer laser, and modification of the electric properties of the source and the drain regions of the TFT is effected by irradiating the source and the drain regions with an irradiation beam in a step independent of the step of crystallizing the channel portion. The process is carried out at low temperature and enables TFTs to be produced effectively and economically without risk of contamination by substrate impurities and with good expectation of a long operational lifetime.
Inventors
- 👤 Hongyong Zhang
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 19:31
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/20; H10P14/38; H10P14/3802; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/031; H10D30/0312; H10D30/0314; H10D30/0321; H10P14/22; H10P14/24; H10P14/29; H10P14/2901; H10P14/2922; H10P14/32; H10P14/3202; H10P14/3204; H10P14/3211; H10P14/3238; H10P14/3242; H10P14/3244; H10P14/3248; H10P14/34; H10P14/3402; H10P14/3404; H10P14/3411; H10P14/3438; H10P14/3441; H10P14/3442; H10P14/3808; H10P14/3816; H10P34/00; H10P34/40; H10P34/42
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
42 words
A method of manufacturing a thin film transistor comprising the steps of: crystallizing a non-single crystal semiconductor layer provided on a substrate; forming source and drain semiconductor layers on the non-single crystal semiconductor layer; and activating the source and drain semiconductor layers.
Claim 2
Dependent Claim
56 words
The method of claim 1 wherein said crystallizing step is carried out by irradiating the non-single crystal semiconductor layer with a first irradiation beam, and said activating step is carried out by irradiating the source and drain semiconductor layers with a second irradiation beam having an energy density different from that of said first irradiation beam.
Claim 3
Dependent Claim
31 words
The method of claim 2 wherein the energy density of said second irradiation beam is smaller than the energy density of said first irradiation beam and is 150 mJ/cm² or less.
Claim 4
Independent Claim
41 words
The method of any preceding claim wherein the formation of said source and drain semiconductor layers is carried out by forming a semiconductor layer by chemical vapor deposition and patterning said semiconductor layer to define said source and drain semiconductor layers.
Claim 5
Dependent Claim
18 words
The method of claim 1 wherein said non-single crystal semiconductor layer comprises an intrinsic or substantially intrinsic semiconductor.
Claim 6
Independent Claim
87 words
A method of manufacturing a thin film transistor comprising source and drain semiconductor regions and a channel region therebetween, said method comprising the steps of: crystallizing said channel region by irradiation with a first irradiation beam; and activating said source and drain regions by irradiating said source and drain regions and said channel region with a second irradiation beam having an energy density of 150 mJ/cm² or less; and wherein the energy density of said second irradiating beam is smaller than that of said first irradiation beam.
Claim 7
Dependent Claim
22 words
The method of claim 10 wherein the irradiation of said source and drain regions is carried out without masking said channel region.
Claim 8
Independent Claim
88 words
A method of manufacturing a thin film transistor comprising the steps of: forming channel, source and drain semiconductor regions of said thin film transistor, forming an insulating film on said channel, source and drain regions; removing portions of said insulating film to form contact openings through said insulating film in said source and drain regions; and activating said source and drain regions by irradiating said source and drain regions and the remaining portions of said insulating film with an irradiation beam with said remaining portions serving as masks.
Claim 9
Dependent Claim
23 words
The method of claim 8 wherein said insulating film comprises silicon oxide, silicon nitride or a multilayer of silicon oxide and silicon nitride.
Claim 10
Dependent Claim
22 words
The method of claim 8 or 9 wherein the upper surface of said channel region is entirely covered by said remaining portion.
Claim 11
Dependent Claim
22 words
The method of claim 8 or 9 or 10 wherein the energy density of said irradiation beam is 150 mJ/cm² or less.
Claim 12
Independent Claim
15 words
The method of any preceding claim wherein said source and drain comprise n-type semiconductor material.
Claim 13
Independent Claim
20 words
The method of any preceding claim wherein irradiation is effected by use of a laser beam and/or a light beam.
Claim 14
Dependent Claim
16 words
A thin film transistor manufactured by a method as claimed in any of the preceding claims.
References Cited (Backward Citations)
No citation records indexed.
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