Thermal Sink Interlayer for PCM Cell Thermal Disturb

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Solution Overview

Problem

Phase change memory (PCM) cell arrays face thermal disturb issues due to heat transfer between adjacent cells, leading to unreliable data storage, especially as integration size increases.

Innovation Solution

Incorporating a thermal sink material with components common to both the chalcogenide material and the top electrode to reduce interface thermal resistance, thereby minimizing heat transfer and maintaining programming characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If PCM cell arrays are downsized to increase integration, then productivity increases, but thermal disturb between adjacent cells worsens

Engineering Contradiction:

Improveintegration densityVSAvoidthermal disturb

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

An interlayer is introduced between the top electrode and chalcogenide material to act as a thermal management intermediary. This interlayer has a thermal conductivity greater than 1 W/m-K, which allows it to effectively conduct heat away from the chalcogenide material, reducing thermal disturb to adjacent cells while maintaining the downsized integration structure

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The thermal conductivity property is locally optimized by introducing the interlayer with specific thermal properties at the critical interface between top electrode and chalcogenide material. This localized thermal management addresses the thermal disturb problem specifically at the heat generation zone without requiring changes to the entire memory array structure

Inventive Principle:

Principle #3Local quality

2Reliability

If thermal sink material is added to reduce thermal disturb, then reliability improves, but device complexity increases

Engineering Contradiction:

Improvedata storage reliabilityVSAvoidcell structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The interlayer serves multiple functions simultaneously: it acts as a thermal sink to reduce thermal disturb, maintains the programming characteristics of the chalcogenide material, and provides a stable interface between the top electrode and chalcogenide material. This multi-functionality improves reliability without proportionally increasing device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If the heated fraction of chalcogenide material is controlled during programming, then thermal disturb is reduced, but manufacturing precision requirements increase

Engineering Contradiction:

Improvethermal disturbVSAvoidheated fraction control precision

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The interlayer with controlled thermal conductivity (greater than 1 W/m-K) acts as a thermal mediator that passively controls the heated fraction of chalcogenide material during programming. This thermal management is achieved through material selection rather than precise control of heating parameters, thereby reducing thermal disturb without significantly increasing manufacturing precision requirements

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The thermal sink material effectively alleviates thermal disturb between adjacent PCM cells, ensuring reliable data storage by controlling the heated fraction of chalcogenide material during programming without significantly impacting individual cell programming.

Implementation Method 1

the thermal sink material effectively alleviates thermal disturb between adjacent PCM cells

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The phase change materials reversibly transform from one phase to another through application of appropriate electrical stimulus

Methodology Applied

Scientific EffectPhase change: Phase Change

Implementation Method 3

A PCM cell may comprise chalcogenide material between a heater and a top electrode. The chalcogenide material may be heated with the heater to cause the desired phase change within the chalcogenide material during programming

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS9570677B2Memory cells, integrated devices, and methods of forming memory cells

Publication Date: 2017.02.14 MICRON TECHNOLOGY INC

AI summary

Some embodiments include integrated devices, such as memory cells. The devices may include chalcogenide material, an electrically conductive material over the chalcogenide material, and a thermal sink between the electrically conductive material and the chalcogenide material. The thermal sink may be of a composition that includes an element in common with the electrically conductive material and includes an element in common with the chalcogenide material. Some embodiments include a method of forming a memory cell. Chalcogenide material may be formed over heater material. Electrically conductive material may be formed over the chalcogenide material. A thermal sink may be formed between the electrically conductive material and the chalcogenide material. The thermal sink may be of a composition that includes an element in common with the electrically conductive material and includes an element in common with the chalcogenide material.