Variable Resistance Memory Device Void Removal via Laser Irradiation

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Solution Overview

Problem

Current semiconductor memory devices face challenges in achieving high performance and low power consumption, particularly in maintaining resistance changes without power interruption, and in efficiently fabricating variable resistance memory devices with complex trench structures.

Innovation Solution

A method for fabricating a variable resistance memory device involves forming a bottom electrode and dielectric layer on a substrate, creating trenches to expose the electrode, depositing a variable resistance layer, and irradiating it with a laser for a specific duration (1.8 μs to 54 μs) to remove voids and ensure effective resistance changes, using a solid laser with adjustable wavelength and energy density to maintain structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a variable resistance layer is formed in a trench structure, then the memory device can achieve nonvolatile data storage, but voids may form in the layer leading to performance degradation

Engineering Contradiction:

Improvedata storage reliabilityVSAvoidvoid formation in variable resistance layer

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by forming a dummy layer in the trench before depositing the variable resistance layer. This dummy layer serves as a foundation that prevents void formation during subsequent deposition processes, ensuring a uniform and defect-free variable resistance layer structure.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The dummy layer acts as an intermediary element between the trench structure and the variable resistance layer. It mediates the interface between these components, providing a stable base that prevents direct contact issues and void formation between the trench walls and the variable resistance material.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If conventional heating methods are used to treat the variable resistance layer, then the overall processing time increases, but using laser irradiation requires precise control of irradiation time to avoid damage

Engineering Contradiction:

Improveprocessing speedVSAvoidlaser irradiation time control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces conventional thermal heating methods with laser irradiation. This substitution enables rapid and localized heating of the variable resistance layer without requiring prolonged processing times, thereby improving productivity while maintaining precise spatial control through the focused laser beam.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent optimizes the laser irradiation parameters, specifically controlling the irradiation time within a precise range of 1.8 to 54 microseconds. This parameter control ensures sufficient heating effect for desired resistance changes while preventing overheating or damage to the delicate trench structure and surrounding materials.

Inventive Principle:

Principle #35Parameter changes

3Loss of time

If high energy density laser is used to remove voids quickly, then processing time decreases, but the structural integrity of the trench may be compromised

Engineering Contradiction:

Improvevoid removal timeVSAvoidtrench structural integrity

Core Design Contradiction:

Loss of timeVSStrength

Solution Approach 1:

The patent carefully adjusts the laser energy density and irradiation time parameters to achieve optimal void removal. By controlling the irradiation time within 1.8 to 54 microseconds and selecting appropriate energy density levels, the method effectively eliminates voids while maintaining the structural integrity of the trench and surrounding dielectric layers.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies partial action by using controlled laser irradiation that is sufficient to remove voids but not excessive enough to damage the trench structure. The irradiation parameters are tuned to achieve just enough energy delivery to eliminate voids while preserving the mechanical integrity of the surrounding materials.

Inventive Principle:

Principle #16Partial or excessive action

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

This approach enables the reliable removal of voids in variable resistance layers, enhancing the performance and endurance of the memory device by ensuring consistent resistance changes and improved program/erase cycle endurance, even with repeated voltage applications.

Implementation Method 1

irradiating the variable resistance layer with a laser, wherein the variable resistance layer is irradiated by the laser for a time of about 1.8 μs to about 54 μs

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentUS11482670B2Method of fabricating a variable resistance memory device

Publication Date: 2022.10.25 SAMSUNG ELECTRONICS CO LTD

AI summary

A method of fabricating a variable resistance memory device includes: forming a bottom electrode on a substrate; forming a dielectric layer on the substrate, wherein the dielectric layer has a first trench that exposes the bottom electrode; forming a variable resistance layer in the first trench; and irradiating the variable resistance layer with a laser, wherein the variable resistance layer is irradiated by the laser for a time of about 1.8 μs to about 54 μs.