US4633284A
Expired / Lapsed
US
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Thin film transistor having an annealed gate oxide and method of making same
Assignee: Energy Conversion Devices Inc
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Filing: 1983-11-08
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Granted: 1986-12-30
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Expires: 2003-11-08
Abstract
Abstract A new and improved thin film field effect transistor and method provides such a transistor having increased operating frequencies and higher output currents. The transistor includes a gate electrode having a non-coplanar surface with respect to the substrate and a deposited semiconductor material overlying the gate electrode to form a current conductor channel between a source and drain. The length of the current conduction channel is determined by the thickness of the gate electrode which can be accurately controlled. As a result, short channel lengths are possible without high precision photolithography for high output currents and fast operating speeds. Further, a gate insulator is disposed between the gate and the deposited semiconductor. The gate insulator, which can be a gate oxide, can be annealed prior to the deposition of the deposited semiconductor to provide enhanced field effect mobilities. This further increases the transistor output currents and operating speeds.
Inventors
- 👤 Gregory L. Hansell
- 👤 Zvi Yaniv
- 👤 Vincent D. Cannella
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 12:52
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/67; H10D30/674; H10D30/6741; H10D30/6728
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
146 words
A thin film field effect transistor formed on a substantially planar surface, said transistor comprising: a gate electrode formed on at least a portion of said substantially planar surface, said gate electrode including a surface portion which is non-parallel to said planar surface; a pair of lateral surface portion adjacent said non-parallel surface portion and extending in respective opposite directions from said non-parallel surface portion; a layer of insulating material overlying said non-parallel surface portion of said gate electrode and extending laterally therefrom in opposite directions; a semiconductor material overlying at least that portion of said layer of insulating material overlying the non-parallel surface portion of the gate electrode; and a source electrode overlying a respective one of said lateral surface portions and a drain electrode overlying the other said lateral surface portion, said drain and source electrodes being in electrical connection with said semiconductor material.
Claim 2
Dependent Claim
146 words
A thin film field effect transistor formed on a substantially planar surface, said transistor comprising: a gate electrode formed on at least a portion of said substantially planar surface, said gate electrode including a surface portion which is non-parallel to said planar surface; a pair of lateral surface portion adjacent said non-parallel surface portion and extending in respective opposite directions from said non-parallel surface portion; a layer of insulating material overlying said non-parallel surface portion of said gate electrode and extending laterally therefrom in opposite directions; a semiconductor material overlying at least that portion of said layer of insulating material overlying the non-parallel surface portion of the gate electrode; and a source electrode overlying a respective one of said lateral surface portions and a drain electrode overlying the other said lateral surface portion, said drain and source electrodes being in electrical connection with said semiconductor material.
Claim 3
Dependent Claim
37 words
A thin film field effect transistor as defined in claim 1 wherein said semiconductor material forms a current conduction channel between said source and drain having a length determined by the effective thickness of said gate electrode.
Claim 4
Dependent Claim
22 words
A thin film field effect transistor as defined in claim 1 wherein said gate electrode comprises a single layer of conductive material.
Claim 5
Dependent Claim
18 words
A thin film field effect transistor as defined in claim 3 wherein said conductive material is a metal.
Claim 6
Dependent Claim
23 words
A thin film field effect transistor as defined in claim 4 wherein said metal is aluminum, chromium, molybdenum or a molybdenum tantalum alloy.
Claim 7
Dependent Claim
35 words
A thin film field effect transistor as defined in claim 1 wherein said gate electrode comprises a second layer of insulating material and a layer of conductive material overlying said second layer of insulating material.
Claim 8
Dependent Claim
18 words
A thin film field effect transistor as defined in claim 6 wherein said conductive material is a metal.
Claim 9
Dependent Claim
23 words
A thin film field effect transistor as defined in claim 7 wherein said metal is aluminum, chromium, molybdenum or a molybdenum tantalum alloy.
Claim 10
Dependent Claim
26 words
A thin film field effect transistor as defined in claim 6 wherein said second layer of insulating material is formed from silicon oxide (SiO x ).
Claim 11
Dependent Claim
21 words
A thin film field effect transistor as defined in claim 1 wherein said insulating material comprises silicon oxide (SiO x ).
Claim 12
Dependent Claim
22 words
A thin film field effect transistor as defined in claim 1 wherein said source electrode and drain electrode each comprises a metal.
Claim 13
Dependent Claim
52 words
A thin film field effect transistor as defined in claim 11 wherein said source electrode and drain electrode further include a first layer of a doped semiconductor between said source metal and said semiconductor material and a second layer of a doped semiconductor between said drain metal and said deposited semiconductor material.
Claim 14
Dependent Claim
30 words
A thin film field effect transistor as defined in claim 1 wherein said non-parallel surface portion of said gate electrode comprises a diagonal surface with respect to said planar surface.
Claim 15
Dependent Claim
19 words
A thin film field effect transistor as defined in claim 1 wherein said semiconductor material includes silicon or germanium.
Claim 16
Dependent Claim
34 words
A thin film field effect transistor as defined in claim 2 wherein said length of said current conduction channel is substantially determined by the length of said non-parallel surface portion of said gate electrode.
Claim 17
Dependent Claim
25 words
A thin film field effect transistor as defined in claim 1 wherein said semiconductor material is an amorphous alloy of silicon including hydrogen or fluorine.
Claim 18
Dependent Claim
25 words
A thin film field effect transistor as defined in claim 13 wherein said semiconductor material is an amorphous alloy of silicon including hydrogen or fluorine.
Claim 19
Dependent Claim
20 words
A thin film field effect transistor as defined in claim 13 wherein said semiconductor material is a polycrystalline silicon alloy.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1989-12-29 | 1990-06-30 | 1990-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-29 | 1994-06-30 | 1994-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-29 | 1998-06-30 | 1998-12-30 | $7700.00 | Window Closed / Lapsed |