IP Library › Granted Patent US 7,745,870
Granted Patent B2
US 7,745,870 · App. 11/626,681 · Granted Jun 29, 2010

Programming and erasing structure for a floating gate memory cell and method of making

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Quick Facts
Patent No.
US 7,745,870
App. No.
11/626,681
Granted
Jun 29, 2010
Kind
B2
Abstract

A floating gate memory cell has a floating gate in which there are two floating gate layers. The top layer is etched to provide a contour in the top layer while leaving the lower layer unchanged. The control gate follows the contour of the floating gate to increase capacitance therebetween. The two layers of the floating gate can be polysilicon separated by a very thin etch stop layer. This etch stop layer is thick enough to provide an etch stop during a polysilicon etch but preferably thin enough to be electrically transparent. Electrons are able to easily move between the two layers. Thus the etch of the top layer does not extend into the lower layer but the first and second layer have the electrical effect for the purposes of a floating gate of being a continuous conductive layer.

Claims (13)

1. A floating gate device a substrate, comprising:

a substrate;

a gate dielectric overlying the substrate;

a floating gate having a first floating gate portion and a second floating gate portion; wherein:

the first floating gate portion overlies the gate dielectric, wherein the first floating gate portion is continuous;

the second floating gate portion overlies the first floating gate portion, wherein the second floating gate portion includes a plurality of separate portions over the first floating gate portion;

an etch stop layer between each of the plurality of separate portions of the second floating gate portion and the first floating gate portion that permits passage of charge during programming and erasing of the floating gate device;

an interlevel dielectric overlying the separate portions of the second floating gate portion and the first floating gate portion; and

a control gate overlying the interlevel dielectric, wherein the control gate extends down in a region between the separate portions and over the first floating gate portion.

2. A floating gate device of claim 1 , wherein the substrate further comprises isolation regions, and wherein the plurality of separate portions of the second floating gate portion are between isolation regions and the region between the separate portions is between the isolation regions.

3. A floating gate device of claim 2 , wherein at least one of the plurality of separate portions of the second floating gate portion is adjacent a sidewall of an isolation region.

4. A floating gate device of claim 1 , wherein the etch stop layer is substantially electrically transparent between each of the plurality of separate portions of the second floating gate portion and the first floating gate portion.

5. A floating gate device of claim 1 , wherein the etch stop layer has a thickness in a range of approximately 15 to 20 Angstroms.

Assignments (26)
CORRECTIVE ASSIGNMENT TO CORRECT THE REMOVE APPLICATION 11759915 AND REPLACE IT WITH APPLICATION 11759935 PREVIOUSLY RECORDED ON REEL 040925 FRAME 0001. ASSIGNOR(S) HEREBY CONFIRMS THE RELEASE OF SECURITY INTEREST. Recorded Feb 17, 2020
From: MORGAN STANLEY SENIOR FUNDING, INC.
To: NXP, B.V. F/K/A FREESCALE SEMICONDUCTOR, INC.
Reel/Frame 052917/0001 →
CORRECTIVE ASSIGNMENT TO CORRECT THE REMOVE APPLICATION 11759915 AND REPLACE IT WITH APPLICATION 11759935 PREVIOUSLY RECORDED ON REEL 040928 FRAME 0001. ASSIGNOR(S) HEREBY CONFIRMS THE RELEASE OF SECURITY INTEREST. Recorded Jan 17, 2020
From: MORGAN STANLEY SENIOR FUNDING, INC.
To: NXP B.V.
Reel/Frame 052915/0001 →
CORRECTIVE ASSIGNMENT TO CORRECT THE REMOVE APPLICATION 11759915 AND REPLACE IT WITH APPLICATION 11759935 PREVIOUSLY RECORDED ON REEL 037486 FRAME 0517. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT AND ASSUMPTION OF SECURITY INTEREST IN PATENTS. Recorded Dec 10, 2019
From: CITIBANK, N.A.
To: MORGAN STANLEY SENIOR FUNDING, INC.
Reel/Frame 053547/0421 →
CORRECTIVE ASSIGNMENT TO CORRECT THE REMOVE APPLICATION 12298143 PREVIOUSLY RECORDED ON REEL 039361 FRAME 0212. ASSIGNOR(S) HEREBY CONFIRMS THE SECURITY AGREEMENT SUPPLEMENT. Recorded Oct 22, 2019
From: NXP B.V.
To: MORGAN STANLEY SENIOR FUNDING, INC.
Reel/Frame 051029/0387 →
CORRECTIVE ASSIGNMENT TO CORRECT THE REMOVE APPLICATION 12298143 PREVIOUSLY RECORDED ON REEL 042985 FRAME 0001. ASSIGNOR(S) HEREBY CONFIRMS THE SECURITY AGREEMENT SUPPLEMENT. Recorded Oct 22, 2019
From: NXP B.V.
To: MORGAN STANLEY SENIOR FUNDING, INC.
Reel/Frame 051029/0001 →
CORRECTIVE ASSIGNMENT TO CORRECT THE REMOVE APPLICATION 12298143 PREVIOUSLY RECORDED ON REEL 038017 FRAME 0058. ASSIGNOR(S) HEREBY CONFIRMS THE SECURITY AGREEMENT SUPPLEMENT. Recorded Oct 22, 2019
From: NXP B.V.
To: MORGAN STANLEY SENIOR FUNDING, INC.
Reel/Frame 051030/0001 →
CORRECTIVE ASSIGNMENT TO CORRECT THE REMOVE APPLICATION 12298143 PREVIOUSLY RECORDED ON REEL 042762 FRAME 0145. ASSIGNOR(S) HEREBY CONFIRMS THE SECURITY AGREEMENT SUPPLEMENT. Recorded Oct 22, 2019
From: NXP B.V.
To: MORGAN STANLEY SENIOR FUNDING, INC.
Reel/Frame 051145/0184 →
RELEASE OF SECURITY INTEREST Recorded Sep 10, 2019
From: MORGAN STANLEY SENIOR FUNDING, INC.
To: NXP B.V.
Reel/Frame 050745/0001 →
RELEASE OF SECURITY INTEREST Recorded Sep 10, 2019
From: MORGAN STANLEY SENIOR FUNDING, INC.
To: NXP B.V.
Reel/Frame 050744/0097 →
CORRECTIVE ASSIGNMENT TO CORRECT THE TO CORRECT THE APPLICATION NO. FROM 13,883,290 TO 13,833,290 PREVIOUSLY RECORDED ON REEL 041703 FRAME 0536. ASSIGNOR(S) HEREBY CONFIRMS THE THE ASSIGNMENT AND ASSUMPTION OF SECURITY INTEREST IN PATENTS.. Recorded Feb 20, 2019
From: MORGAN STANLEY SENIOR FUNDING, INC.
To: SHENZHEN XINGUODU TECHNOLOGY CO., LTD.
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CORRECTIVE ASSIGNMENT TO CORRECT THE REMOVE APPLICATION 12681366 PREVIOUSLY RECORDED ON REEL 039361 FRAME 0212. ASSIGNOR(S) HEREBY CONFIRMS THE SECURITY AGREEMENT SUPPLEMENT. Recorded May 9, 2017
From: NXP B.V.
To: MORGAN STANLEY SENIOR FUNDING, INC.
Reel/Frame 042762/0145 →
CORRECTIVE ASSIGNMENT TO CORRECT THE REMOVE APPLICATION 12681366 PREVIOUSLY RECORDED ON REEL 038017 FRAME 0058. ASSIGNOR(S) HEREBY CONFIRMS THE SECURITY AGREEMENT SUPPLEMENT. Recorded May 9, 2017
From: NXP B.V.
To: MORGAN STANLEY SENIOR FUNDING, INC.
Reel/Frame 042985/0001 →
CORRECTIVE ASSIGNMENT TO CORRECT THE REMOVE PATENTS 8108266 AND 8062324 AND REPLACE THEM WITH 6108266 AND 8060324 PREVIOUSLY RECORDED ON REEL 037518 FRAME 0292. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT AND ASSUMPTION OF SECURITY INTEREST IN PATENTS. Recorded Feb 1, 2017
From: CITIBANK, N.A.
To: MORGAN STANLEY SENIOR FUNDING, INC.
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CORRECTIVE ASSIGNMENT TO CORRECT THE NATURE OF CONVEYANCE LISTED CHANGE OF NAME SHOULD BE MERGER AND CHANGE PREVIOUSLY RECORDED AT REEL: 040652 FRAME: 0180. ASSIGNOR(S) HEREBY CONFIRMS THE MERGER AND CHANGE OF NAME. Recorded Jan 12, 2017
From: FREESCALE SEMICONDUCTOR INC.
To: NXP USA, INC.
Reel/Frame 041354/0148 →
CHANGE OF NAME Recorded Nov 8, 2016
From: FREESCALE SEMICONDUCTOR INC.
To: NXP USA, INC.
Reel/Frame 040652/0180 →
RELEASE OF SECURITY INTEREST Recorded Nov 7, 2016
From: MORGAN STANLEY SENIOR FUNDING, INC.
To: NXP B.V.
Reel/Frame 040928/0001 →
RELEASE OF SECURITY INTEREST Recorded Sep 21, 2016
From: MORGAN STANLEY SENIOR FUNDING, INC.
To: NXP, B.V., F/K/A FREESCALE SEMICONDUCTOR, INC.
Reel/Frame 040925/0001 →
CORRECTIVE ASSIGNMENT TO CORRECT THE REMOVE APPLICATION 12092129 PREVIOUSLY RECORDED ON REEL 038017 FRAME 0058. ASSIGNOR(S) HEREBY CONFIRMS THE SECURITY AGREEMENT SUPPLEMENT. Recorded Jul 14, 2016
From: NXP B.V.
To: MORGAN STANLEY SENIOR FUNDING, INC.
Reel/Frame 039361/0212 →
SUPPLEMENT TO THE SECURITY AGREEMENT Recorded Jun 16, 2016
From: FREESCALE SEMICONDUCTOR, INC.
To: MORGAN STANLEY SENIOR FUNDING, INC.
Reel/Frame 039138/0001 →
SECURITY AGREEMENT SUPPLEMENT Recorded Mar 7, 2016
From: NXP B.V.
To: MORGAN STANLEY SENIOR FUNDING, INC.
Reel/Frame 038017/0058 →
ASSIGNMENT AND ASSUMPTION OF SECURITY INTEREST IN PATENTS Recorded Jan 13, 2016
From: CITIBANK, N.A.
To: MORGAN STANLEY SENIOR FUNDING, INC.
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ASSIGNMENT AND ASSUMPTION OF SECURITY INTEREST IN PATENTS Recorded Jan 12, 2016
From: CITIBANK, N.A.
To: MORGAN STANLEY SENIOR FUNDING, INC.
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PATENT RELEASE Recorded Dec 21, 2015
From: CITIBANK, N.A., AS COLLATERAL AGENT
To: FREESCALE SEMICONDUCTOR, INC.
Reel/Frame 037356/0553 →
PATENT RELEASE Recorded Dec 21, 2015
From: CITIBANK, N.A., AS COLLATERAL AGENT
To: FREESCALE SEMICONDUCTOR, INC.
Reel/Frame 037356/0143 →
PATENT RELEASE Recorded Dec 21, 2015
From: CITIBANK, N.A., AS COLLATERAL AGENT
To: FREESCALE SEMICONDUCTOR, INC.
Reel/Frame 037354/0640 →
SECURITY AGREEMENT Recorded Nov 6, 2013
From: FREESCALE SEMICONDUCTOR, INC.
To: CITIBANK, N.A., AS NOTES COLLATERAL AGENT
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