US4442507A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrically programmable read-only memory stacked above a semiconductor substrate
Assignee: Unisys Corp
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Filing: 1981-02-23
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Granted: 1984-04-10
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Expires: 2001-02-23
Abstract
Abstract In the disclosed memory, address decode means are integrated into a surface of a substrate, for addressing cells in the memory; an insulating layer covers the address decode means and the substrate; an array of spaced-apart memory cell select lines lie on the insulating layer; and outputs from the address decode means respectively couple through the insulating layer to the select lines. Each cell of the memory is comprised of a pair of the select lines and further includes a resistive means between that pair which irreversibly switches from a relatively high resistance state to a relatively low resistance state upon the application of a threshold voltage thereacross, and the resistance states are representative of the information in the cell.
Inventors
- 👤 Bruce B. Roesner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:46
CPC Classifications
G; G11; G11C; G11C17/00; G11C17/14; G11C17/16; G11C17/18
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
146 words
An electrically programmable read only memory having memory cells on an insulating layer which overlies a semiconductor substrate; each of said memory cells comprising: a first semiconductor material having a polycrystalline grain structure; a metallic compound in contact with said first semiconductor material forming a Schottky diode therewith; and a second semiconductor material serially coupled within said cell to said Schottky diode; said second semiconductor material consisting essentially of a single element semiconductor selected from the group of Si, Ge, C, and α-Sn, having a crystalline grain size which is smaller than that of said polycrystalline semiconductor material, and having a concentration of dopant atoms of less than 10 17 atoms/cm 3 ; whereby said second semiconductor material will exhibit a high resistance that will irreversibly switch to a low resistance without the flowing of any metal therethrough upon the application of a threshold voltage thereacross.
Claim 2
Dependent Claim
146 words
An electrically programmable read only memory having memory cells on an insulating layer which overlies a semiconductor substrate; each of said memory cells comprising: a first semiconductor material having a polycrystalline grain structure; a metallic compound in contact with said first semiconductor material forming a Schottky diode therewith; and a second semiconductor material serially coupled within said cell to said Schottky diode; said second semiconductor material consisting essentially of a single element semiconductor selected from the group of Si, Ge, C, and α-Sn, having a crystalline grain size which is smaller than that of said polycrystalline semiconductor material, and having a concentration of dopant atoms of less than 10 17 atoms/cm 3 ; whereby said second semiconductor material will exhibit a high resistance that will irreversibly switch to a low resistance without the flowing of any metal therethrough upon the application of a threshold voltage thereacross.
Claim 3
Dependent Claim
30 words
A memory according to claim 1 wherein said first semiconductor material contains dopant atoms which are substitutionally disposed, and said second semiconductor material contains dopant atoms which are interstitially disposed.
Claim 4
Dependent Claim
44 words
A memory according to claim 1 wherein said first semiconductor material is subjected to temperatures of over 600° C. whereas said second semiconductor material is subjected to temperatures of only less than 600° C. to achieve their respective relatively large and small grain sizes.
Claim 5
Dependent Claim
27 words
A memory according to claim 1 wherein said metallic compound is disposed between and in direct contact with said first semiconductor material and said second semiconductor material.
Claim 6
Dependent Claim
27 words
A memory according to claim 1 wherein said first semiconductor material is disposed between and in direct contact with said metallic compound and said second semiconductor material.
Claim 7
Dependent Claim
38 words
A memory according to claim 1 wherein said substrate has a major surface, and said first semiconductor material, said metallic compound, and said second semiconductor material are stacked on top of each other essentially perpendicular to said surface.
Claim 8
Dependent Claim
67 words
A memory according to claim 1 which further includes: address decode means, integrated into a surface of said substrate, for generating signals to address said cells in said memory; a plurality of spaced-apart memory cell select lines on said insulating layer coupled to said memory cells; and means for coupling said signals from said address decode means through said insulating layer to said memory cell select lines.
Claim 9
Dependent Claim
12 words
A memory according to claim 1 wherein said dopant atoms are N-type.
Claim 10
Dependent Claim
12 words
A memory according to claim 1 wherein said dopant atoms are P-type.
Claim 11
Dependent Claim
16 words
A memory according to claim 1 wherein said second semiconductor material contains essentially no dopant atoms.
Claim 12
Dependent Claim
138 words
An electrically programmable memory cell comprising: a first semiconductor material having a polycrystalline grain structure; a metallic compound in contact with said first semiconductor material forming a Schottky diode therewith; and a second semiconductor material forming a Schottky diode therewith; and a second semiconductor material serially coupled within said cell to said Schottky diode; said second semiconductor material consisting essentially of a single element semiconductor selected from the group of Si, Ge, C, and α-Sn, having a crystalline grain size which is smaller than that of said polycrystalline semiconductor material, and having a concentration of dopant atoms of less than 10 17 atoms/cm 3 ; whereby said second semiconductor material will exhibit a high resistance that will irreversibly switch to a low resistance without the flowing of any metal therethrough upon the application of a threshold voltage thereacross.
Claim 13
Dependent Claim
138 words
An electrically programmable memory cell comprising: a first semiconductor material having a polycrystalline grain structure; a metallic compound in contact with said first semiconductor material forming a Schottky diode therewith; and a second semiconductor material forming a Schottky diode therewith; and a second semiconductor material serially coupled within said cell to said Schottky diode; said second semiconductor material consisting essentially of a single element semiconductor selected from the group of Si, Ge, C, and α-Sn, having a crystalline grain size which is smaller than that of said polycrystalline semiconductor material, and having a concentration of dopant atoms of less than 10 17 atoms/cm 3 ; whereby said second semiconductor material will exhibit a high resistance that will irreversibly switch to a low resistance without the flowing of any metal therethrough upon the application of a threshold voltage thereacross.
Claim 14
Dependent Claim
107 words
An electrically programmable memory cell comprising: a pair of spaced apart conductors for applying a threshold voltage thereacross; and a semiconductor materially serially coupled between said conductors for receiving said threshold voltage; said semiconductor material consisting essentially of a single element semiconductor selected from the group of Si, Ge, C, and α-Sn, having a crystalline grain size which is smaller than polycrystalline and having dopant atoms which are interstitial in the crystals and not substitutional; whereby said semiconductor material will exhibit a high resistance that will irreversibly switch to a low resistance without the flowing of any metal therethrough upon the application of said threshold voltage thereacross.
Claim 15
Dependent Claim
107 words
An electrically programmable memory cell comprising: a pair of spaced apart conductors for applying a threshold voltage thereacross; and a semiconductor materially serially coupled between said conductors for receiving said threshold voltage; said semiconductor material consisting essentially of a single element semiconductor selected from the group of Si, Ge, C, and α-Sn, having a crystalline grain size which is smaller than polycrystalline and having dopant atoms which are interstitial in the crystals and not substitutional; whereby said semiconductor material will exhibit a high resistance that will irreversibly switch to a low resistance without the flowing of any metal therethrough upon the application of said threshold voltage thereacross.
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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) | 1987-04-10 | 1987-10-10 | 1988-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-10 | 1991-10-10 | 1992-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-10 | 1995-10-10 | 1996-04-10 | $7700.00 | Window Closed / Lapsed |