Non-volatile Memory Cell With Heating Element for Oxide Repair

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Solution Overview

Problem

Current non-volatile memory cells, such as EEPROMs and flash EPROMs, have limited erase-program cycles due to damage from electron tunneling through thin oxide layers, leading to charge leakage and reduced storage capacity over time.

Innovation Solution

Incorporating a localized heating element that anneals the tunnel/thin gate dielectric after programming or erasing, reducing damage and extending the number of cycles by repairing the oxide layers, while also potentially lowering programming and erasing voltages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electron tunneling is used for programming and erasing memory cells, then data storage and retrieval are enabled, but the oxide layers suffer damage leading to limited erase-program cycles

Engineering Contradiction:

Improvenumber of erase-program cyclesVSAvoidoxide layer damage from electron tunneling

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies a heating element to heat the tunnel oxide layer after electron tunneling operations. This thermal treatment repairs the damage caused by electron tunneling, converting the harmful effect into a beneficial repair process that extends the number of erase-program cycles the memory cell can withstand

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Ease of operation

If conventional programming and erasing methods are used, then memory operations can be performed, but high voltages are required which increase device complexity

Engineering Contradiction:

Improveprogramming and erasing voltage requirementsVSAvoidvoltage generation and control circuitry

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent introduces a heating element that changes the thermal parameter of the oxide layer. By heating the oxide, the programming and erasing operations can be performed at lower voltages, thereby reducing the complexity of voltage generation and control circuitry

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Significantly increases the number of erase-program cycles, improving the durability and reliability of non-volatile memory cells by repairing oxide damage and reducing voltage requirements.

Implementation Method 1

Incorporating a localized heating element that anneals the tunnel/thin gate dielectric after programming or erasing

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

anneals the tunnel/thin gate dielectric after programming or erasing, reducing damage and extending the number of cycles by repairing the oxide layers

Methodology Applied

Scientific EffectAnnealing: Annealing

Implementation Method 3

EEPROMS are programmed and erased electrically by a process known as Fowler-Nordheim tunneling

Methodology Applied

Scientific EffectFowler-Nordheim tunneling:

Data Source

PatentUS8669157B2Non-volatile memory cell having a heating element and a substrate-based control gate

Publication Date: 2014.03.11 NAT SEMICON CORP

AI summary

The number of times that a non-volatile memory (NVM) can be programmed and erased is substantially increased by utilizing a localized heating element that anneals the oxide that is damaged by tunneling charge carriers when the NVM is programmed and erased. The program and erase voltages are also reduced when heat from the heating element is applied prior to programming and erasing.