US5776811A
Expired / Lapsed
US
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Simplified process for fabricating flash eeprom cells
Assignee: Cypress Semiconductor Corp
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Filing: 1996-01-04
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Granted: 1998-07-07
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Expires: 2016-01-04
Abstract
Abstract A simplified fabrication procedure for making flash EEPROM memory cells is disclosed. The method comprises performing a double-diffuse (deep) junction implant after the shallow source/drain of the memory cell have been implanted and formed. A high energy double-diffuse implant is used to replace separate, individual implant and diffusion steps which results in a memory cell having, less damage to its substrate.
Inventors
- 👤 Hsingya Arthur Wang
- 👤 Jian Chen
- 👤 Paul J. Steffan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:03
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0411; H10D30/60; H10D30/68; H10D30/681; H10D30/684; H10D30/685
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
122 words
A process of forming a semiconductor device on a wafer, comprising the steps of: (a) forming a plurality of layers of semiconductor material on said wafer, said plurality of layers providing a floating gate and a control gate; (b) implanting a shallow source junction on said wafer by diffusing a first dopant into the substrate, said shallow source junction having a surface; (c) oxidizing the surface of said shallow source junction directly subsequent to step (b); and (d) implanting a high energy double diffuse source junction on said wafer by diffusing a second dopant into the substrate directly subsequent to step (c), said double diffuse source junction including said shallow source junction and a deep source junction below said shallow source junction.
Claim 2
Dependent Claim
122 words
A process of forming a semiconductor device on a wafer, comprising the steps of: (a) forming a plurality of layers of semiconductor material on said wafer, said plurality of layers providing a floating gate and a control gate; (b) implanting a shallow source junction on said wafer by diffusing a first dopant into the substrate, said shallow source junction having a surface; (c) oxidizing the surface of said shallow source junction directly subsequent to step (b); and (d) implanting a high energy double diffuse source junction on said wafer by diffusing a second dopant into the substrate directly subsequent to step (c), said double diffuse source junction including said shallow source junction and a deep source junction below said shallow source junction.
Claim 3
Dependent Claim
45 words
The process of claim 1, further including the steps of: (e) forming contact regions on said shallow source junction; and (f) forming a metal on said source junction to enable the metal to operate as a contact between said semiconductor device and an external device.
Claim 4
Dependent Claim
40 words
The process of claim 1, wherein step (b) further comprises the step of: (b1) implanting said shallow source junction with arsenic at an energy of about 60 KeV and with an implant dose of about 7.0×10 15 cm -2 .
Claim 5
Dependent Claim
20 words
The process of claim 1, wherein step (d) is performed at an energy range of 30 keV to 300 keV.
Claim 6
Dependent Claim
16 words
The process of claim 4, wherein step (d) is performed at an energy of 200 keV.
Claim 7
Dependent Claim
25 words
The process of claim 1, wherein said shallow source junction has a depth of about 0.2 μm from the surface of said shallow source junction.
Claim 8
Dependent Claim
25 words
The process of claim 1, wherein said deep source junction has a depth of about 0.6 μm from the surface of said shallow source junction.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2001-07-06 | 2002-01-05 | 2002-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-07-06 | 2006-01-05 | 2006-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-07-06 | 2010-01-05 | 2010-07-07 | $7700.00 | Window Closed / Lapsed |