Nonvolatile Resistance Change Element Rectification Layer

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Solution Overview

Problem

Conventional nonvolatile resistance change elements with internal rectification functions exhibit low reliability, making it difficult to achieve highly reliable mass storage devices due to the low probability of rectification properties, which hinders the miniaturization and capacity enhancement of storage devices.

Innovation Solution

A nonvolatile resistance change element is designed with a rectification function layer containing Ag, Ni, or Co between the semiconductor variable resistance layer and the lower electrode, allowing for reliable rectification by changing band alignment based on voltage polarity, thereby controlling current flow effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rectifier elements are inserted in series with resistance change elements, then the rectification function is improved, but the memory cell height increases and device miniaturization becomes difficult

Engineering Contradiction:

Improverectification functionVSAvoidmemory cell height

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The patent merges the rectifier element and resistance change element into a single integrated memory cell structure. The rectifier layer and variable resistance layer are formed as stacked layers within the same cell, eliminating the need for separate series-connected elements and thereby reducing memory cell height while maintaining the rectification function.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a nested structure where the rectifier layer is positioned between the first electrode and the variable resistance layer. This nesting arrangement allows the rectification function to be embedded within the resistance change element structure, reducing overall device complexity and height.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Device complexity

If conventional resistance change elements with internal rectification are used, then device complexity is reduced, but the rectification occurrence probability is low and reliability is insufficient

Engineering Contradiction:

Improvedevice complexityVSAvoidrectification occurrence probability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent optimizes the composition and structure of the variable resistance layer to achieve reliable resistance change. Specifically, it uses a semiconductor layer with controlled doping concentration (1×10^19 to 1×10^21 atoms/cm³) and forms metal filaments through controlled diffusion, ensuring both rectification function and high occurrence probability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures including a semiconductor layer combined with metal elements (Ag, Ni, Co) that form variable resistance regions. This composite approach enables both the rectification function and reliable resistance change behavior to coexist within the same layer structure.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If the variable resistance layer uses simple metal deposition, then manufacturing is simple, but the resistance change reliability is insufficient

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidresistance change reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent performs preliminary doping of the semiconductor layer before metal deposition. The semiconductor layer is pre-doped with phosphorus or arsenic at controlled concentrations, which prepares the layer to form reliable metal filaments when metal atoms are subsequently diffused during resistance change operation, ensuring both manufacturing feasibility and reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces a semiconductor layer as an intermediary between the electrode and the metal variable resistance layer. This semiconductor layer with controlled doping acts as a mediator that enables reliable filament formation and resistance change while maintaining manufacturing simplicity through standard semiconductor processing techniques.

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 solution achieves a highly reliable rectification function with improved occurrence probability, enabling the development of mass storage devices with enhanced reliability and capacity.

Implementation Method 1

allowing for reliable rectification by changing band alignment based on voltage polarity

Methodology Applied

Scientific EffectBand alignment:

Data Source

PatentUS9882127B2Nonvolatile resistance change element

Publication Date: 2018.01.30 KIOXIA CORP

AI summary

According to one embodiment, a nonvolatile resistance change element includes a first electrode, a second electrode, a semiconductor layer and a first layer. The first electrode includes at least one of Ag, Ni, Co, Al, Zn, Ti, and Cu. The semiconductor layer is sandwiched between the first and second electrodes. The first layer is provided between the second electrode and the semiconductor layer and contains an element included in the semiconductor layer and at least one of Ag, Ni, and Co.