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US5008722A Expired / Lapsed US ⏱️ 0.0 years remaining

Non-volatile memory

Assignee: Texas Instruments Inc
•
Filing: 1989-05-31
•
Granted: 1991-04-16
•
Expires: 2009-05-31
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Abstract

Abstract A cross point EPROM array has trenches to provide improved isolation between adjacent buried N+ bitlines at locations where the adjacent buried N+ bitlines are not separated by a FAMOS transistor. This results in improved leakage current, improved punchthrough voltage characteristics, and in improved programmability for the cell.

Inventors

  • 👤 Agerico L. Esquivel

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 21:39
CPC Classifications
H; H10; H10B; H10B41/00; H10B41/30; H10B69/00; H10D; H10D64/00; H10D64/01; H10D64/031; H10D64/035; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/0125; H10W10/0126; H10W10/014; H10W10/10; H10W10/13; H10W10/17; Y; Y10; Y10S; Y10S257/00; Y10S257/903

Claims Analysis

Total Claims: 38
Claim 1
Independent Claim 125 words
A non-volatile memory cell array comprising: a semiconductor body; a plurality of bitline diffusions; a plurality of wordlines which are not parallel to said bit line diffusions, said plural wordlines being respectively mutually parallel; a plurality of floating gates underlying said wordlines at locations in between said bitline diffusions; a plurality of transistor channel locations, each disposed substantially under a floating gate; and a plurality of isolation trenches, each filled with a dielectric material and extending into said semicondutor body, each of said trenches disposed between a pair of channel locations which are disposed between the same bitline diffusions and which are associated with adjacent wordlines, said trenches having edges aligned with said floating gates so that said floating gates do not overlap said trenches.
Claim 2
Dependent Claim 125 words
A non-volatile memory cell array comprising: a semiconductor body; a plurality of bitline diffusions; a plurality of wordlines which are not parallel to said bit line diffusions, said plural wordlines being respectively mutually parallel; a plurality of floating gates underlying said wordlines at locations in between said bitline diffusions; a plurality of transistor channel locations, each disposed substantially under a floating gate; and a plurality of isolation trenches, each filled with a dielectric material and extending into said semicondutor body, each of said trenches disposed between a pair of channel locations which are disposed between the same bitline diffusions and which are associated with adjacent wordlines, said trenches having edges aligned with said floating gates so that said floating gates do not overlap said trenches.
Claim 3
Dependent Claim 20 words
The device of claim 1, wherein said floating gates are not crystalline and comprise at least 30% atomic of silicon.
Claim 4
Dependent Claim 19 words
The device of claim 1, wherein said wordlines are not crystalline and comprise at least 30% atomic of silicon.
Claim 5
Dependent Claim 15 words
The device of claim 1, wherein said trenches are filled with a deposited dielectric material.
Claim 6
Dependent Claim 18 words
The device of claim 1, wherein said trenches are at least 25% as deep as said bitline diffusions.
Claim 7
Dependent Claim 30 words
The device of claim 1, wherein said transistor channel locations define a floating gate transistor having portions of respective ones of said bitline diffusions as respective source and drain electrodes.
Claim 8
Dependent Claim 45 words
The device of claim 1, further comprising: a plurality of bitline insulator strips, each bitline insulator strip overlying an associated bitline diffusion, said bitline insulator strips each having an equivalent dielectric thickness at leaset ten times that of the dielectric beneath said respective floating gates.
Claim 9
Dependent Claim 26 words
The device of claim 1, wherein said trenches are at least ten times as deep as the thickness of the dielectric beneath said respective floating gates.
Claim 10
Dependent Claim 145 words
A non-volatile memory cell array comprising: a semiconductor body; a plurality of substantially parallel bitline insulator strips on said semiconductor body; a plurality of bitline diffusions each underlying one of said bitline insulator strips; a plurality of wordlines which are not parallel to said bitline diffusions, said plural wordlines being respectively mutually substantially parallel; a plurality of floating gates underlying said wordlines at locations in between said bitline diffusions; a plurality of transistor channel locations, each disposed substantially under a floating gate; and a plurality of isolation trenches, each filled with a dielectric material and extending into said semiconductor body, each of said trenches disposed between a pair of channel locations which are disposed between the same bitline diffusions and which are associated with adjacent wordlines, and each having edges aligned with said floating gates so that said floating gates do not overlap said trenches.
Claim 11
Dependent Claim 145 words
A non-volatile memory cell array comprising: a semiconductor body; a plurality of substantially parallel bitline insulator strips on said semiconductor body; a plurality of bitline diffusions each underlying one of said bitline insulator strips; a plurality of wordlines which are not parallel to said bitline diffusions, said plural wordlines being respectively mutually substantially parallel; a plurality of floating gates underlying said wordlines at locations in between said bitline diffusions; a plurality of transistor channel locations, each disposed substantially under a floating gate; and a plurality of isolation trenches, each filled with a dielectric material and extending into said semiconductor body, each of said trenches disposed between a pair of channel locations which are disposed between the same bitline diffusions and which are associated with adjacent wordlines, and each having edges aligned with said floating gates so that said floating gates do not overlap said trenches.
Claim 12
Dependent Claim 20 words
The device of claim 9, wherein said floating gates are not crystalline and comprise at least 30% atomic of silicon.
Claim 13
Dependent Claim 19 words
The device of claim 9, wherein said wordlines are not crystalline and comprise at least 30% atomic of silicon.
Claim 14
Dependent Claim 15 words
The device of claim 9, wherein said trenches are filled with a deposited dielectric material.
Claim 15
Dependent Claim 18 words
The device of claim 9, wherein said trenches are at least 25% as deep as said bitline diffusions.
Claim 16
Dependent Claim 30 words
The device of claim 9, wherein said transistor channel locations define a floating gate transistor having portions of respective ones of said bitline diffusions as respective source and drain electrodes.
Claim 17
Dependent Claim 28 words
The device of claim 9, wherein said bitline insulator strips have an equivalent dielectric thickness at least ten times that of the dielectric beneath said respective floating gates.
Claim 18
Dependent Claim 26 words
The device of claim 9, wherein said trenches are at least ten times as deep as the thickness of the dielectric beneath said respective floating gates.
Claim 19
Dependent Claim 113 words
A non-volatile memory cell array comprising: a semiconductor body; a plurality of bitline diffusions; a plurality of wordlines which are not parallel to said bitline diffusions; a plurality of floating gates underlying said wordlines at locations in between said bitline diffusions; a plurality of transistor channel locations, each disposed substantially under a floating gate; and a plurality of isolation trenches filled with dielectric material and extending into said semiconductor body, each of said trenches disposed between a pair of channel locations which are disposed between the same bitline diffusions and which are associated with adjacent wordlines, each of said trenches aligned with said wordlines so that said wordlines do not overlap said trenches.
Claim 20
Dependent Claim 113 words
A non-volatile memory cell array comprising: a semiconductor body; a plurality of bitline diffusions; a plurality of wordlines which are not parallel to said bitline diffusions; a plurality of floating gates underlying said wordlines at locations in between said bitline diffusions; a plurality of transistor channel locations, each disposed substantially under a floating gate; and a plurality of isolation trenches filled with dielectric material and extending into said semiconductor body, each of said trenches disposed between a pair of channel locations which are disposed between the same bitline diffusions and which are associated with adjacent wordlines, each of said trenches aligned with said wordlines so that said wordlines do not overlap said trenches.
Claim 21
Dependent Claim 20 words
The device of claim 17, wherein said floating gates are not crystalline and comprise at least 30% atomic of silicon.
Claim 22
Dependent Claim 19 words
The device of claim 17, wherein said wordlines are not crystalline and comprise at least 30% atomic of silicon.
Claim 23
Dependent Claim 15 words
The device of claim 17, wherein said trenches are filled with a deposited dielectric material.
Claim 24
Dependent Claim 18 words
The device of claim 17, wherein said trenches are at least 25% as deep as said bitline diffusions.
Claim 25
Dependent Claim 30 words
The device of claim 17, wherein said transistor channel locations define a floating gate transistor having portions of respective ones of said bitline diffusions as respective source and drain electrodes.
Claim 26
Dependent Claim 28 words
The device of claim 17, wherein said bitline insulator strips have an equivalent dielectric thickness at least ten times that of the dielectric beneath said respective floating gates.
Claim 27
Dependent Claim 26 words
The device of claim 17, wherein said trenches are at least ten times as deep as the thickness of the dielectric beneath said respective floating gates.
Claim 28
Dependent Claim 134 words
A non-volatile memory cell array comprising: a semiconductor body; a plurality of substantially parallel bitline insulator strips on said semiconductor body; a plurality of bitline diffusions each underlying one of said bitline insulator strips; a plurality of wordlines which are not parallel to said bitline diffusions; a plurality of floating gates underlying said wordlines at locations in between said bitline diffusions; a plurality of transistor channel locations, each disposed substantially under a floating gate; and a plurality of isolation trenches filled with dielectric material and extending into said semiconductor body, each of said trenches disposed between a pair of channel locations which are disposed between the same bitline diffusions and which are associated with adjacent wordlines, each of said trenches aligned with said wordlines so that said wordlines do not overlap onto said trenches.
Claim 29
Dependent Claim 134 words
A non-volatile memory cell array comprising: a semiconductor body; a plurality of substantially parallel bitline insulator strips on said semiconductor body; a plurality of bitline diffusions each underlying one of said bitline insulator strips; a plurality of wordlines which are not parallel to said bitline diffusions; a plurality of floating gates underlying said wordlines at locations in between said bitline diffusions; a plurality of transistor channel locations, each disposed substantially under a floating gate; and a plurality of isolation trenches filled with dielectric material and extending into said semiconductor body, each of said trenches disposed between a pair of channel locations which are disposed between the same bitline diffusions and which are associated with adjacent wordlines, each of said trenches aligned with said wordlines so that said wordlines do not overlap onto said trenches.
Claim 30
Dependent Claim 20 words
The device of claim 25, wherein said floating gates are not crystalline and comprise at least 30% atomic of silicon.
Claim 31
Dependent Claim 19 words
The device of claim 25, wherein said wordlines are not crystalline and comprise at least 30% atomic of silicon.
Claim 32
Dependent Claim 15 words
The device of claim 25, wherein said trenches are filled with a deposited dielectric material.
Claim 33
Dependent Claim 18 words
The device of claim 25, wherein said trenches are at least 25% as deep as said bitline diffusions.
Claim 34
Dependent Claim 30 words
The device of claim 25, wherein said transistor channel locations define a floating gate transistor having portions of respective ones of said bitline diffusions as respective source and drain electrodes.
Claim 35
Dependent Claim 28 words
The device of claim 25, wherein said bitline insulator strips have an equivalent dielectric thickness at least ten times that of the dielectric beneath said respective floating gates.
Claim 36
Dependent Claim 26 words
The device of claim 25, wherein said trenches are at least ten times as deep as the thickness of the dielectric beneath said respective floating gates.
Claim 37
Dependent Claim 15 words
The device of claim 17, wherein said word lines are perpendicular to said bitline diffusions.
Claim 38
Dependent Claim 19 words
The device of claim 25, wherein said plurality of word lines are perpendicular to said plurality of bitline diffusions.

References Cited (Backward Citations)

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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) 1994-04-15 1994-10-15 1995-04-16 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1998-04-15 1998-10-15 1999-04-16 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2002-04-15 2002-10-15 2003-04-16 $7700.00 Window Closed / Lapsed

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