US4201603A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of fabricating improved short channel MOS devices utilizing selective etching and counterdoping of polycrystalline silicon
Assignee: RCA Corp
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Filing: 1978-12-04
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Granted: 1980-05-06
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Expires: 1998-12-04
Abstract
Abstract A method for fabricating a short channel MOS device is described wherein the conductivity of the gate member is increased by a factor of about 2.5 by counterdoping a P-type doped polycrystalline line with an N-type dopant.
Inventors
- 👤 Joseph H. Scott, Jr.
- 👤 Alfred C. Ipri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:19
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/031; H10D30/0321; H10D30/0323; H10D30/0312; H10D30/0314; H10D30/0327; H10D30/60; H10D30/67; H10D30/6729; H10D30/673; H10P; H10P32/00; H10P32/30; H10P32/302; H10P50/00; H10P50/60; H10P50/66; H10P50/663; H10P50/667; H10P76/00; H10P76/40; Y; Y10; Y10S; Y10S148/00; Y10S148/106; Y10S148/122; Y10S148/15; Y10S438/00; Y10S438/914; Y10S438/919; Y10S438/967
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
120 words
In a method of making a semiconductor device which includes the steps of forming a uniform layer of polycrystalline silicon having an exposed edge over the silicon body, forming a masking layer on the polycrystalline silicon layer, the masking layer extending at least to the exposed edge of the polycrystalline silicon layer, embedding a dopant into the exposed edge of the polycrystalline silicon layer for a desired distance laterally along the polycrystalline silicon layer in order to transform the uniform layer to a selectively etchable layer, removing the masking layer, and selectively etching the polycrystalline silicon layer to remove the undoped portion thereof, the improvement comprising: counterdoping the doped portions of the polycrystalline silicon layer to raise the conductivity thereof.
Claim 2
Dependent Claim
120 words
In a method of making a semiconductor device which includes the steps of forming a uniform layer of polycrystalline silicon having an exposed edge over the silicon body, forming a masking layer on the polycrystalline silicon layer, the masking layer extending at least to the exposed edge of the polycrystalline silicon layer, embedding a dopant into the exposed edge of the polycrystalline silicon layer for a desired distance laterally along the polycrystalline silicon layer in order to transform the uniform layer to a selectively etchable layer, removing the masking layer, and selectively etching the polycrystalline silicon layer to remove the undoped portion thereof, the improvement comprising: counterdoping the doped portions of the polycrystalline silicon layer to raise the conductivity thereof.
Claim 3
Dependent Claim
29 words
The method in accordance with claim 1, in which: the dopant utilized to produce the selectively etchable layer is a P-type dopant; and the counterdopant is an N-type dopant.
Claim 4
Dependent Claim
28 words
The method in accordance with claim 2, in which: the P-type dopant is boron; and the N-type dopant is selected from the group consisting of phosphorus and arsenic.
Claim 5
Dependent Claim
47 words
The method in accordance with claim 3, in which: the doped portion of the polycrystalline silicon layer is doped to the limit of solubility of the P-type dopant; and the doped portion of the polycrystalline silicon layer is counterdoped to the solubility limit of the N-type dopant.
Claim 6
Dependent Claim
25 words
The method in accordance with claim 4, in which: the P type dopant is of the order of about 2.3×10 20 /cm 3 conductivity modifiers.
Claim 7
Dependent Claim
35 words
The method in accordance with claim 5, in which: the counterdoping is done with phosphorus as the counterdopant; and the counterdoping is carried on at about 1050° C. for a period of about 15 minutes.
Claim 8
Dependent Claim
28 words
The method in accordance with claim 6, in which: the solubility limit of the phosphorus counterdopant is of the order of about 1.4×10 21 /cm 3 conductivity modifiers.
Claim 9
Dependent Claim
38 words
The method in accordance with claim 7, in which: the body of silicon is an island formed on an insulative substrate; and the insulative substrate is selected from the group consisting of sapphire, spinel and monocrystalline beryllium oxide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-05-06 | 1983-11-05 | 1984-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-05-06 | 1987-11-05 | 1988-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-05-06 | 1991-11-05 | 1992-05-06 | $7700.00 | Window Closed / Lapsed |