Resistance Change Memory Diode Thickness Reduction

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Solution Overview

Problem

Resistance change memories, particularly in cross-point type arrays, face challenges in achieving the required characteristics for rectifying elements, such as large current during forward bias, small current during reverse bias, and high breakdown voltage, which necessitate increased thickness, compromising three-dimensional integration of memory cell arrays.

Innovation Solution

The use of diodes with specific structures like SIS, MIS, SMIS, and MIM, which include insulating layers between semiconductor or metal layers, allows for reduced thickness while maintaining rectifying characteristics, enabling efficient set/reset operations and read operations with improved aspect ratios for three-dimensional integration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the thickness of the rectifying element is increased to achieve large forward current, small reverse current, and high breakdown voltage, then the rectifying characteristics are improved, but the aspect ratio of the trench becomes large which is disadvantageous for three-dimensional integration

Engineering Contradiction:

Improverectifying characteristicsVSAvoidthickness of rectifying element

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The rectifying element is segmented into multiple thin film layers (semiconductor layer, insulating layer, and electrode layers) stacked in sequence, replacing a single thick structure with a multi-layer composite structure that achieves the required electrical characteristics while maintaining a smaller overall thickness

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The rectifying element uses composite material structure combining semiconductor materials (such as silicon, silicon germanium), insulating materials (such as silicon oxide, silicon nitride), and electrode materials, creating a multi-material system that provides both the required electrical characteristics and reduced thickness

Inventive Principle:

Principle #40Composite materials

2Reliability

If the thickness of the rectifying element is increased to satisfy forward bias current, reverse bias current, and breakdown voltage requirements, then the set/reset operation and read operation can be correctly performed, but the device complexity and manufacturing difficulty increase due to large aspect ratio trenches

Engineering Contradiction:

Improveoperation correctnessVSAvoidmanufacturing process difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the structural parameters of the rectifying element by transitioning from a single thick layer to a multi-layer thin film structure, altering the thickness, material composition, and layer configuration to achieve the required electrical characteristics with reduced overall dimensions

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

These diodes effectively decrease the thickness of rectifying elements while maintaining necessary characteristics, reducing power consumption, enhancing operating speed, and simplifying read operations, thus facilitating the integration of resistance change memories.

Implementation Method 1

a diode including an anode layer, a cathode layer and an insulating layer therebetween

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS8907318B2Resistance change memory

Publication Date: 2014.12.09 KIOXIA CORP

AI summary

A resistance change memory includes a first conductive line extending in a first direction, a second conductive line extending in a second direction which is crossed to the first direction, a cell unit including a memory element and a rectifying element connected in series between the first and second conductive lines, and a control circuit which is connected to both of the first and second conductive lines. The control circuit controls a voltage to change a resistance of the memory element between first and second values reversibly. The rectifying element is a diode including an anode layer, a cathode layer and an insulating layer therebetween.