US4268951A
Expired / Lapsed
US
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Submicron semiconductor devices
Assignee: Boeing North American Inc
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Filing: 1978-11-13
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Granted: 1981-05-26
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Expires: 1998-11-13
Abstract
Abstract Semiconductor devices with gate dimensions as small as 0.25 microns square have been fabricated using electron beam lithography and dry processing techniques. In particular, silicon gate, N-channel, metal-oxide-semiconductor (NMOS) field-effect-transistors (FET) have been produced. The devices and the process are especially adapted to bulk silicon based transistors.
Inventors
- 👤 Michael T. Elliott
- 👤 Michael R. Splinter
- 👤 Addison B. Jones
- 👤 John P. Reekstin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 03:42
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0223; H10P; H10P50/00; H10P50/73; H10P76/00; H10P76/20; H10P76/202; H10P76/40; H10P76/408; H10P76/4085; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/0121; H10W10/0124; H10W10/0125; H10W10/0126; H10W10/10; H10W10/13
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
154 words
A method of fabricating semiconductor devices having dimensions less than one micron, comprising the steps of masking a suitable semiconductor substrate with etchant resist mask, etching portions of the substrate in accordance with the pattern defined by the etchant resist mask, implanting selected dopants into said substrate after masking, growing an insulating layer onto the etched and implanted substrate, further implanting the substrate in the region under said mask after removing the mask and after said growing step such that said substrate has dopants implanted therein at different depths, growing a polycrystalline layer on said substrate after said further implanting step, masking and etching said polycrystalline layer to leave a portion over said region, additionally implanting said substrate using said polycrystalline portion as a mask to define self-aligned portions of a semiconductor device, masking said additionally implanted substrate to define metallization patterns, and metallizing said substrate to provide electrical contacts to selected portions thereof.
Claim 2
Independent Claim
154 words
A method of fabricating semiconductor devices having dimensions less than one micron, comprising the steps of masking a suitable semiconductor substrate with etchant resist mask, etching portions of the substrate in accordance with the pattern defined by the etchant resist mask, implanting selected dopants into said substrate after masking, growing an insulating layer onto the etched and implanted substrate, further implanting the substrate in the region under said mask after removing the mask and after said growing step such that said substrate has dopants implanted therein at different depths, growing a polycrystalline layer on said substrate after said further implanting step, masking and etching said polycrystalline layer to leave a portion over said region, additionally implanting said substrate using said polycrystalline portion as a mask to define self-aligned portions of a semiconductor device, masking said additionally implanted substrate to define metallization patterns, and metallizing said substrate to provide electrical contacts to selected portions thereof.
Claim 3
Dependent Claim
24 words
The method recited in claim 1 including the further steps of, implanting into said additionally implanted substrate an additional dopant to prevent junction spike-through.
Claim 4
Dependent Claim
23 words
The method recited in claim 1 wherein said etchant resist mask includes a layer of silicon nitride and a layer of silicon oxide.
Claim 5
Dependent Claim
15 words
The method recited in claim 3 wherein said etchant mask includes a layer of titanium.
Claim 6
Dependent Claim
29 words
The method recited in claim 4 wherein said titanium layer defines an etchant mask for said silicon nitride layer which, in turn, defines an etchant mask for said substrate.
Claim 7
Dependent Claim
20 words
The method recited in claim 1 wherein the dopant utilized in said implanting and said further implanting steps is Boron.
Claim 8
Dependent Claim
20 words
The method recited in claim 1 including a depletion mode implanting step wherein additional dopant is implanted into said substrate.
Claim 9
Dependent Claim
12 words
The method recited in claim 7 wherein said additional dopant is Phosphorus.
Claim 10
Dependent Claim
22 words
The method recited in claim 7 including, masking said substrate to define the areas wherein depletion mode devices are to be provided.
Claim 11
Dependent Claim
16 words
The method recited in claim 3 wherein said silicon nitride layer is deposited by CVD techniques.
Claim 12
Dependent Claim
15 words
The method recited in claim 11 wherein said etching steps comprise an ion milling procedure.
Claim 13
Dependent Claim
17 words
The method recited in claim 1 wherein said substrate comprises a wafer of <100>, 2 ohm-cm silicon.
Claim 14
Dependent Claim
34 words
The method recited in claim 1 wherein said implanting step comprises an ion implantation procedure for forming a channel stop and said etchant resist mask operates as a mask for said ion implantation procedure.
Claim 15
Dependent Claim
19 words
The method recited in claim 1 wherein said polycrystalline material comprises polysilicon which is deposited over a gate oxide.
Claim 16
Dependent Claim
15 words
The method recited in claim 1 including, annealing said substrate after said additional implanting step.
Claim 17
Dependent Claim
20 words
The method recited in claim 1 including providing bonding pads during said metallization step, and finally annealing the device formed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-05-25 | 1984-11-24 | 1985-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-25 | 1988-11-24 | 1989-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-25 | 1992-11-24 | 1993-05-26 | $7700.00 | Window Closed / Lapsed |