US4697330A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Floating gate memory process with improved dielectric
Assignee: Texas Instruments Inc
•
Filing: 1986-05-27
•
Granted: 1987-10-06
•
Expires: 2006-05-27
Abstract
Abstract The dielectric between the floating gate and the control gate, in an EEPROM or other floating gate memory is made by forming an oxide/nitride stack over the (first polysilicon) control gate. This dielectric not only provides a very high specific capacitance, which is desired to provide tight coupling of the control to the floating gate, but also provides excellent dielectric integrity. Moreover, the thickness of this dielectric layer does not exhibit any uncontrolled increase during exposure to second gate oxidation. Thus, the polysilicon-to-polysilicon dielectric is not only of high specific capacitance and high integrity, it is also very uniform.
Inventors
- 👤 James L. Paterson
- 👤 Boger A. Haken
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:23
CPC Classifications
H; H10; H10B; H10B41/00; H10B41/40; H10B41/42; H10B41/43; H10B41/47; H10D; H10D64/00; H10D64/60; H10D64/66; H10D64/68; H10D64/681
Claims Analysis
Total Claims: 48
Claim 1
Independent Claim
159 words
A method for making a floating gate memory, comprising the steps of: providing a substrate having a semiconductor surface portion; forming a first gate insulator layer on said substrate; forming a first insulated conductor layer over said substrate, said conductor layer being polycrystalline and comprising silicon; forming a layer of silicon dioxide over said first conductive layer; forming a layer of silicon nitride over said first conductive layer; patterning said first insulated conductor layer, to define a plurality of desired floating gates; providing an oxidizing atmosphere to form gate insulators in selected locations; forming a second conductive layer in predetermined locations, said second conductive layer comprising control gate portions over said floating gates in said first conductive layer; and implanting a plurality of source/drain regions on opposite sides of the respective ones of said floating gates; whereby a floating gate memory cell having very high specific capacitance between said respective floating gates and said respective control gates is formed.
Claim 2
Independent Claim
159 words
A method for making a floating gate memory, comprising the steps of: providing a substrate having a semiconductor surface portion; forming a first gate insulator layer on said substrate; forming a first insulated conductor layer over said substrate, said conductor layer being polycrystalline and comprising silicon; forming a layer of silicon dioxide over said first conductive layer; forming a layer of silicon nitride over said first conductive layer; patterning said first insulated conductor layer, to define a plurality of desired floating gates; providing an oxidizing atmosphere to form gate insulators in selected locations; forming a second conductive layer in predetermined locations, said second conductive layer comprising control gate portions over said floating gates in said first conductive layer; and implanting a plurality of source/drain regions on opposite sides of the respective ones of said floating gates; whereby a floating gate memory cell having very high specific capacitance between said respective floating gates and said respective control gates is formed.
Claim 3
Dependent Claim
26 words
The method of claim 1, wherein said step of forming a layer of silicon dioxide over said first conductive layer is performed by growing said oxide.
Claim 4
Dependent Claim
30 words
The method of claim 1, wherein said step of forming a layer of silicon dioxide over said first conductive layer is performed by low-pressure chemical vapor deposition of said oxide.
Claim 5
Dependent Claim
16 words
The method of claim 1, wherein said first insulated conductor layer consists essentially of polycrystalline silicon.
Claim 6
Dependent Claim
39 words
The method of claim 1, wherein said substrate has a silicon surface portion, and wherein said step of providing an oxidizing atmosphere to form gate insulators in selected locations grows silicon dioxide on portions of said silicon surface portion.
Claim 7
Dependent Claim
49 words
The method of claim 1, wherein said substrate has a silicon surface portion, and wherein said step of providing an oxidizing atmosphere to form gate insulators in selected locations grows silicon dioxide on portions of said silicon surface portion which are not protected by said layer of silicon nitride.
Claim 8
Dependent Claim
27 words
The method of claim 1, wherein said step of forming a layer of silicon nitride over said first conductive layer is performed by low-pressure chemical vapor deposition.
Claim 9
Dependent Claim
27 words
The method of claim 1, wherein said step of forming a layer of silicon nitride over said first conductive layer is performed by plasma-enhanced chemical vapor deposition.
Claim 10
Dependent Claim
69 words
The method of claim 1, wherein said step of forming a layer of silicon nitride over said first conductive layer is performed by low-pressure chemical vapor deposition, and an oxide layer is formed over said nitride layer by low-pressure chemical vapor deposition before said nitride layer is exposed to an atmospheric ambient, all prior to said step of providing an oxidizing atmosphere to form gate insulators in selected locations.
Claim 11
Dependent Claim
24 words
The method of claim 1, wherein said second conductive layer consists essentially of a layered structure including both polycrystalline silicon and metal silicide portions.
Claim 12
Dependent Claim
16 words
The method of claim 1, wherein said second conductive layer consists essentially of doped polycrystalline silicon.
Claim 13
Dependent Claim
16 words
The method of claim 1, wherein said second conductive layer consists essentially of a metal silicide.
Claim 14
Dependent Claim
15 words
The method of claim 1, wherein said second conductive layer consists essentially of a metal.
Claim 15
Dependent Claim
25 words
The method of claim 1, wherein said first insulated conductor layer consists essentially of a layered structure including both polycrystalline silicon and metal silicide portions.
Claim 16
Dependent Claim
17 words
The method of claim 1, wherein said first insulated conductor layer consists essentially of doped polycrystalline silicon.
Claim 17
Dependent Claim
17 words
The method of claim 1, wherein said first insulated conductor layer consists essentially of a metal silicide.
Claim 18
Independent Claim
155 words
A method for making a floating gate memory, comprising the steps of: (a) providing a body having a semiconductor surface portion; (b) forming a first insulated conductor layer over said semiconductor portion; (c) forming an oxide layer over said first conductor layer; (d) forming a layer of silicon nitride over said first conductor layer; (e) patterning said first insulated conductor layer, to define a plurality of desired floating gates; (f) providing an oxidizing atmosphere to form gate insulators in selected locations of said semiconductor surface portion; (g) forming a second conductive layer in predetermined locations, said second conductive layer comprising control gate portions over said floating gates in said first conductor layer; and (h) providing a plurality of source/drain regions on opposite sides of the respective ones of said floating gates; (i) whereby a floating gate memory cell having very high specific capacitance between said respective floating gates and said respective control gates is formed.
Claim 19
Independent Claim
155 words
A method for making a floating gate memory, comprising the steps of: (a) providing a body having a semiconductor surface portion; (b) forming a first insulated conductor layer over said semiconductor portion; (c) forming an oxide layer over said first conductor layer; (d) forming a layer of silicon nitride over said first conductor layer; (e) patterning said first insulated conductor layer, to define a plurality of desired floating gates; (f) providing an oxidizing atmosphere to form gate insulators in selected locations of said semiconductor surface portion; (g) forming a second conductive layer in predetermined locations, said second conductive layer comprising control gate portions over said floating gates in said first conductor layer; and (h) providing a plurality of source/drain regions on opposite sides of the respective ones of said floating gates; (i) whereby a floating gate memory cell having very high specific capacitance between said respective floating gates and said respective control gates is formed.
Claim 20
Dependent Claim
26 words
The method of claim 17, wherein said step of forming a layer of silicon dioxide over said first conductive layer is performed by growing said oxide.
Claim 21
Dependent Claim
30 words
The method of claim 17, wherein said step of forming a layer of silicon dioxide over said first conductive layer is performed by low-pressure chemical vapor deposition of said oxide.
Claim 22
Dependent Claim
16 words
The method of claim 17, wherein said first insulated conductor layer consists essentially of polycrystalline silicon.
Claim 23
Dependent Claim
39 words
The method of claim 17, wherein said substrate has a silicon surface portion, and wherein said step of providing an oxidizing atmosphere to form gate insulators in selected locations grows silicon dioxide on portions of said silicon surface portion.
Claim 24
Dependent Claim
49 words
The method of claim 17, wherein said substrate has a silicon surface portion, and wherein said step of providing an oxidizing atmosphere to form gate insulators in selected locations grows silicon dioxide on portions of said silicon surface portion which are not protected by said layer of silicon nitride.
Claim 25
Dependent Claim
27 words
The method of claim 17, wherein said step of forming a layer of silicon nitride over said first conductive layer is performed by low-pressure chemical vapor deposition.
Claim 26
Dependent Claim
27 words
The method of claim 17, wherein said step of forming a layer of silicon nitride over said first conductive layer is performed by plasma-enhanced chemical vapor deposition.
Claim 27
Dependent Claim
69 words
The method of claim 17, wherein said stpe of forming a layer of silicon nitride over said first conductive layer is performed by low-pressure chemical vapor deposition, and an oxide layer is formed over said nitride layer by low-pressure chemical vapor deposition before said nitride layer is exposed to an atmospheric ambient, all prior to said step of providing an oxidizing atmosphere to form gate insulators in selected locations.
Claim 28
Dependent Claim
24 words
The method of claim 17, wherein said second conductive layer consists essentially of a layered structure including both polycrystalline silicon and metal silicide portions.
Claim 29
Dependent Claim
16 words
The method of claim 17, wherein said second conductive layer consists essentially of doped polycrystalline silicon.
Claim 30
Dependent Claim
16 words
The method of claim 17, wherein said second conductive layer consists essentially of a metal silicide.
Claim 31
Dependent Claim
15 words
The method of claim 17, wherein said second conductive layer consists essentially of a metal.
Claim 32
Dependent Claim
25 words
The method of claim 17, wherein said first insulated conductor layer consists essentially of a layered structure including both polycrystalline silicon and metal silicide portions.
Claim 33
Dependent Claim
17 words
The method of claim 17, wherein said first insulated conductor layer consists essentially of doped polycrystalline silicon.
Claim 34
Dependent Claim
17 words
The method of claim 17, wherein said first insulated conductor layer consists essentially of a metal silicide.
Claim 35
Independent Claim
177 words
A method for making a floating gate memory, comprising the steps of: (a) providing a body having a silicon surface portion; (b) forming a first insulated conductor layer comprising polycrystalline silicon over said semiconductor portion; (c) depositing an oxide layer over said first conductor layer; (d) depositing a layer of silicon nitride over said first conductor layer, said oxide layer and said nitride layer having a total combined thickness of less than 600 Angstroms; (e) patterning said first insulated conductor layer, to define a plurality of desired floating gates; (f) providing an oxidizing atmosphere to form silicon dioxide gate insulators in selected locations of said silicon surface portion; (g) forming a second conductive layer in predetermined locations, said second conductive layer comprising control gate portions over said floating gates in said first conductive layer; and (h) providing a plurality of source/drain regions on opposite sides of the respective ones of said floating gates; (i) whereby a floating gate memory cell having very high specific capacitance between said respective floating gates and said respective control gates is formed.
Claim 36
Independent Claim
177 words
A method for making a floating gate memory, comprising the steps of: (a) providing a body having a silicon surface portion; (b) forming a first insulated conductor layer comprising polycrystalline silicon over said semiconductor portion; (c) depositing an oxide layer over said first conductor layer; (d) depositing a layer of silicon nitride over said first conductor layer, said oxide layer and said nitride layer having a total combined thickness of less than 600 Angstroms; (e) patterning said first insulated conductor layer, to define a plurality of desired floating gates; (f) providing an oxidizing atmosphere to form silicon dioxide gate insulators in selected locations of said silicon surface portion; (g) forming a second conductive layer in predetermined locations, said second conductive layer comprising control gate portions over said floating gates in said first conductive layer; and (h) providing a plurality of source/drain regions on opposite sides of the respective ones of said floating gates; (i) whereby a floating gate memory cell having very high specific capacitance between said respective floating gates and said respective control gates is formed.
Claim 37
Dependent Claim
30 words
The method of claim 33, wherein said step of forming a layer of silicon dioxide over said first conductve layer is performed by low-pressure chemical vapor deposition of said oxide.
Claim 38
Dependent Claim
17 words
The method of claim 33, wherein said first insulated conductor layer consists essentially of doped polycrystalline silicon.
Claim 39
Dependent Claim
40 words
The method of claim 33, wherein said step of providing an oxidizing atmosphere to form gate insulators in selected locations grows silicon dioxide on portions of said silicon surface portion which are not protected by said layer of silicon nitride.
Claim 40
Dependent Claim
27 words
The method of claim 33, wherein said step of forming a layer of silicon nitride over said first conductive layer is performed by low-pressure chemical vapor deposition.
Claim 41
Dependent Claim
27 words
The method of claim 33, wherein said step of forming a layer of silicon nitride over said first conductive layer is performed by plasma-enhanced chemical vapor deposition.
Claim 42
Dependent Claim
69 words
The method of claim 33, wherein said step of forming a layer of silicon nitride over said first conductive layer is performed by low-pressure chemical vapor deposition, and an oxide layer is formed over said nitride layer by low-pressure chemical vapor deposition before said nitride layer is exposed to an atmospheric ambient, all prior to said step of providing an oxidizing atmosphere to form gate insulators in selected locations.
Claim 43
Dependent Claim
24 words
The method of claim 33, wherein said second conductive layer consists essentially of a layered structure including both polycrystalline silicon and metal silicide portions.
Claim 44
Dependent Claim
16 words
The method of claim 33, wherein said second conductive layer consists essentially of doped polycrystalline silicon.
Claim 45
Dependent Claim
16 words
The method of claim 33, wherein said second conductive layer consists essentially of a metal silicide.
Claim 46
Dependent Claim
15 words
The method of claim 33, wherein said second conductive layer consists essentially of a metal.
Claim 47
Dependent Claim
25 words
The method of claim 33, wherein said first insulated conductor layer consists essentially of a layered structure including both polycrystalline silicon and metal silicide portions.
Claim 48
Dependent Claim
17 words
The method of claim 33, wherein said first insulated conductor layer consists essentially of doped polycrystalline silicon.
References Cited (Backward Citations)
US4532022A
Cited
US4581622A
Cited
US4451904A
Cited
US4456978A
Cited
US4409723A
Cited
US4495693A
Cited
US4630086A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-10-05 | 1991-04-06 | 1991-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-05 | 1995-04-06 | 1995-10-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-05 | 1999-04-06 | 1999-10-06 | $7700.00 | Window Closed / Lapsed |