Concave Bottom Electrode for Memory Cell Reliability

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Solution Overview

Problem

The reliability and electrical performance of resistance switching memory cell structures in semiconductor devices are compromised due to sensitivity to the profile and uniformity of the bottom electrode configuration, leading to instability and errors in data storage.

Innovation Solution

A semiconductor device with a memory cell structure featuring a concave bottom electrode and a continuous surface profile between the top surfaces of the bottom electrode and the insulating layer, which improves the structural profile and uniformity, enhancing the reliability and electrical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a flat bottom electrode configuration is used, then the manufacturing process is simple, but the reliability and electrical performance deteriorate due to sensitivity to profile uniformity

Engineering Contradiction:

Improvedata storage stabilityVSAvoidbottom electrode profile complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The bottom electrode is designed with a concave curved surface instead of a flat profile. This curvature eliminates sharp edges and corners that cause non-uniform electric fields, thereby improving the reliability and electrical performance of the memory device while maintaining manufacturing feasibility through standard deposition techniques

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Reliability

If the bottom electrode has a continuous surface profile with the insulating layer, then the electrical performance improves, but the manufacturing precision requirements increase

Engineering Contradiction:

Improveelectrical performanceVSAvoidsurface profile uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The invention changes the geometric parameters of the bottom electrode by creating a concave profile with specific depth and curvature characteristics. This parameter modification ensures continuous surface transition with the insulating layer, improving electrical performance while the parameters are controlled within standard manufacturing tolerances

Inventive Principle:

Principle #35Parameter changes

3Reliability

If edges and corners are eliminated from the bottom electrode, then bit error rates reduce, but the device structure becomes more complex

Engineering Contradiction:

Improvedata retention and enduranceVSAvoidelectrode structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

By introducing a concave curved surface to the bottom electrode, all sharp edges and corners are eliminated. The curved geometry distributes the electric field uniformly without creating concentration points that would cause bit errors, while the structure remains a single continuous electrode component rather than multiple assembled parts

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS9859336B1Semiconductor device including a memory cell structure

Publication Date: 2018.01.02 MACRONIX INTERNATIONAL CO LTD

AI summary

A semiconductor device including a memory cell structure is provided, and the memory cell structure includes an insulating layer disposed above a substrate, a bottom electrode embedded in the insulating layer, a resistance switching layer disposed on the bottom electrode, and a top electrode disposed on the resistance switching layer and covering the resistance switching layer. Also, the bottom electrode has a concave top surface lower than a flat upper surface of the insulating layer.