# US 8,542,539 B2 · NAND flash memory programming

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- Number: US 8,542,539 B2
- Document ID: US8542539B2
- Status: Granted
- Kind: B2
- Application number: 13/189,678
- Filed: 2011-07-25
- Published: 2011-11-17
- Granted: 2013-09-24
- Earliest claimed: 2006-08-28
- Assignees: Micron Technology, Inc.
- Applicants: Ramin Ghodsi; Qiang Tang
- Inventors: Ramin Ghodsi; Qiang Tang
- Web page: https://patentgrep.com/patent/US8542539B2

## CPC

- G11C 16/10: Programming or data input circuits
- G11C 16/0483: {comprising cells having several storage transistors connected in series}
- G11C 16/12: Programming voltage switching circuits
- G11C: STATIC STORES (semiconductor memory devices H10B)

## Abstract

A method of charging a floating gate in a nonvolatile memory cell comprises bringing a substrate channel within the memory cell to a first voltage, bringing a control gate to a programming voltage, and floating the substrate channel voltage while the control gate is at the programming voltage. Memory devices include state machines or controllers operable to perform the described method, and operation of such a state machine, memory device, and information handling system are described.

## Claims

### Claim 1

A method comprising:
bringing a channel voltage of a channel of a memory cell to a first voltage;
bringing a control gate of the memory cell to a programming voltage, wherein the programming voltage is higher than the first voltage; and
floating the channel voltage while the control gate is at the programming voltage, wherein bringing the channel voltage to the first voltage comprises coupling at least one of a source or a drain of a string of memory cells including the memory cell to the first voltage, and floating the channel voltage comprises electrically floating voltage on at least one of a source line or a drain line electrically coupled to the channel of the memory cell.

### Claim 2 (depends on 1)

The method of claim 1, wherein the first voltage is a ground voltage, and the programming voltage is at least 15 volts.

### Claim 3 (depends on 1)

The method of claim 1, wherein floating the channel voltage while the control gate is at the programming voltage comprises floating the channel voltage during at least half of the time the control gate is at the programming voltage.

### Claim 4 (depends on 1)

The method of claim 1, wherein the programming voltage is a voltage sufficient to cause electrons to move from a channel of the memory cell to a charge storage structure electrically insulated from the channel and from the control gate.

### Claim 5 (depends on 1)

The method of claim 1, wherein floating the channel voltage while the control gate is at the programming voltage comprises floating the channel voltage during the entire time the control gate is at the programming voltage.

### Claim 6

A method comprising:
applying a programming voltage to a control gate of a memory cell in a programming operation that programs data into the memory cell; and
allowing a channel of the memory cell to float during a portion of the programming operation of the data into the memory cell by electrically floating voltage on at least one of a source line or a drain line electrically coupled to the channel of the memory cell.

### Claim 7 (depends on 6)

The method of claim 6, wherein the portion comprises a significant portion of the programming operation.

### Claim 8 (depends on 6)

The method of claim 6, wherein allowing the channel of the cell to float during the portion of the programming operation comprises allowing the channel of the cell to float during the portion of the programming operation after the voltage applied to the control gate reaches a level sufficiently high to cause tunneling of electrons from the channel onto a charge storage structure of the memory cell.

### Claim 9 (depends on 6)

The method of claim 6, further comprising:
grounding the channel before the programming operation begins.

### Claim 10 (depends on 6)

The method of claim 6, wherein allowing a channel of the cell to float during a portion of a programming operation comprises allowing a channel of the cell to float before or as the programming voltage is applied.