IP Library Granted Patent US 10,707,220
Granted Patent B2
US 10,707,220 · App. 15/691,806 · Granted Jul 7, 2020

Ferroelectric memory and methods of forming the same

Inventors: Ashonita A. Chavan (Boise, ID); Alessandro Calderoni (Boise, ID); D. V. Nirmal Ramaswamy (Boise, ID)
Assignee: Micron Technology, Inc.
H01L27/11507H01L27/10876H01L28/90H01L29/4236
View Patent ↗
Loading inventors, assignments & file history…
Monitor This Case
Get email alerts when status or documents change.
Order Certified Copies
Most orders are placed with the USPTO same day — all within 24 business hours.
Order via The Patent Place →
Pre-filled with this patent's details
Quick Facts
Patent No.
US 10,707,220
App. No.
15/691,806
Granted
Jul 7, 2020
Kind
B2
Abstract

Ferroelectric memory and methods of forming the same are provided. An example memory cell can include a buried recessed access device (BRAD) formed in a substrate and a ferroelectric capacitor formed on the BRAD.

Claims (29)

1. A memory cell, comprising:

a buried recessed access device (BRAD) formed in a substrate, wherein a gate of the BRAD is formed between a first source/drain region and a second source/drain region corresponding to the BRAD, and wherein the gate is formed below an upper surface of at least one of the first and the second source/drain region;

a ferroelectric capacitor formed on the BRAD, wherein a bottom electrode of the ferroelectric capacitor is coupled to the first source/drain region, and wherein a top electrode of the ferroelectric capacitor is coupled to the second source/drain region; and

a conductive contact coupled to the top electrode and to the second source/drain region, wherein the conductive contact is not positioned in alignment with the ferroelectric capacitor and an adjacent ferroelectric capacitor of an adjacent memory cell of a same row of memory cells and wherein the conductive contact is formed at least partially on the second source/drain region and at least partially on a dielectric material formed in a substrate corresponding to an isolation region between the same row of memory cells and an adjacent row.

2. The memory cell of claim 1 , wherein the memory cell achieves a 4F 2 architecture with F being a feature size corresponding to the memory cell.

3. The memory cell of claim 1 , wherein the ferroelectric capacitor is a container capacitor having a ferroelectric material formed therein.

4. The memory cell of claim 3 , wherein the ferroelectric material is formed on sidewalls of an electrode material in a container of the container capacitor.

5. The memory cell of claim 1 , wherein the ferroelectric capacitor is on pitch with the BRAD.

6. A ferroelectric random access memory (FeRAM), comprising:

a first plurality of ferroelectric capacitors coupled in series between a first conductive line and a second conductive line; and

a second plurality of ferroelectric capacitors coupled in series between the first conductive line and a third conductive line;

wherein each of the first and second plurality of ferroelectric capacitors are coupled to a respective buried recessed access device (BRAD) having a gate electrode formed beneath the corresponding ferroelectric capacitor;

wherein each of the first plurality of ferroelectric capacitors are formed in a container and include:

a bottom electrode formed on sidewalls of the container and on a bottom electrode contact;

a ferroelectric material formed in the container and on sidewalls of the bottom electrode;

a top electrode formed in the container and on sidewalls of the ferroelectric material, the top electrode coupled to a source/drain region of the corresponding BRAD via a conductive pillar, wherein a distance from the conductive pillar to a first side of a ferroelectric capacitor of the first plurality is different than a distance from the conductive pillar to a second side of the ferroelectric capacitor of the first plurality; and

wherein the conductive pillar is not positioned in alignment with the first plurality and second plurality of ferroelectric capacitors of a same row of ferroelectric capacitors and wherein at least a portion of the conductive pillar is formed at least partially on an isolation region formed in a substrate separating BRADs corresponding to the first plurality of ferroelectric capacitors and BRADs corresponding to the second plurality of ferroelectric capacitors.

7. The FeRAM of claim 6 , wherein the first side faces the second plurality of ferroelectric capacitors and the second side opposes the second plurality of ferroelectric capacitors.

8. The FeRAM of claim 6 , wherein the conductive pillar is located between the first plurality of ferroelectric capacitors and the second plurality of ferroelectric capacitors.

9. The FeRAM of claim 6 , wherein the first conductive line is a plate line, the second conductive line is a bit line, and the third conductive line is a different bit line.

10. The FeRAM of claim 6 , wherein at least one of the first plurality of ferroelectric capacitors comprises a ferroelectric storage material selected from the group including:

lead zirconate titanate (PZT); and

strontium bismuth tantalate (SBT);

a hafnium oxide based material; and

a zirconium oxide based material.

11. The FeRAM of claim 10 , wherein the hafnium oxide based material and the zirconium oxide based material are doped with at least one of: silicon (Si), aluminum (Al), germanium (Ge), magnesium (Mg), calcium (Ca), strontium (Sr), niobium (Nb), yttrium (Y), barium (Ba), titanium (Ti), and/or a combination thereof.

12. The FeRAM of claim 6 , further comprising:

a first select device configured to selectively couple the first plurality of ferroelectric capacitors to the first conductive line; and

a second select device configured to selectively couple the second plurality of ferroelectric capacitors to the first conductive line.

Assignments (7)
RELEASE OF SECURITY INTEREST Recorded Nov 12, 2019
From: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
To: MICRON TECHNOLOGY, INC.; MICRON SEMICONDUCTOR PRODUCTS, INC.
Reel/Frame 051028/0001 →
RELEASE OF SECURITY INTEREST Recorded Oct 10, 2019
From: MORGAN STANLEY SENIOR FUNDING, INC., AS COLLATERAL AGENT
To: MICRON TECHNOLOGY, INC.
Reel/Frame 050709/0838 →
RELEASE OF SECURITY INTEREST Recorded Jul 20, 2018
From: U.S. BANK NATIONAL ASSOCIATION, AS AGENT
To: MICRON TECHNOLOGY, INC.
Reel/Frame 046597/0333 →
SECURITY INTEREST Recorded Jul 13, 2018
From: MICRON TECHNOLOGY, INC.; MICRON SEMICONDUCTOR PRODUCTS, INC.
To: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
Reel/Frame 047540/0001 →
SUPPLEMENT NO. 6 TO PATENT SECURITY AGREEMENT Recorded Nov 1, 2017
From: MICRON TECHNOLOGY, INC.
To: U.S. BANK NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 044348/0253 →
SUPPLEMENT NO. 6 TO PATENT SECURITY AGREEMENT Recorded Nov 1, 2017
From: MICRON TECHNOLOGY, INC.
To: MORGAN STANLEY SENIOR FUNDING, INC., AS COLLATERAL AGENT
Reel/Frame 044653/0333 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Aug 31, 2017
From: CHAVAN, ASHONITA A.; CALDERONI, ALESSANDRO; RAMASWAMY, D.V. NIRMAL
To: MICRON TECHNOLOGY, INC.
Reel/Frame 043455/0941 →
Continuity (2)
Continuation 14263610 · Apr 28, 2014
Related Publication 20180006044A1 · Jan 4, 2018
Cited By (1)
US 12,666,659