MIM Top Electrode Diffusion Barrier for Higher Breakdown Voltage

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Solution Overview

Problem

The existing MIM capacitors face issues with electrical breakdown and top electrode shorting due to void formation in the capacitor dielectric layer, caused by diffusive species reacting with the dielectric layer during removal and cleaning processes.

Innovation Solution

A top electrode structure with a diffusion barrier layer is introduced, comprising a first top electrode layer with columnar grains, a diffusion barrier layer formed using atomic layer deposition and annealing with nitrogen, and a second top electrode layer. This configuration blocks the diffusion of species through the diffusion barrier layer, preventing void formation in the dielectric layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a top electrode is formed directly over the capacitor dielectric layer, then the manufacturing process is simple, but diffusive species react with the dielectric layer causing void formation and electrical breakdown

Engineering Contradiction:

Improveelectrical breakdown resistanceVSAvoidtop electrode structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A diffusion barrier layer is introduced as an intermediary between the top electrode and the capacitor dielectric layer. This barrier layer prevents diffusive species from the top electrode from reacting with the dielectric layer, thereby eliminating void formation and electrical breakdown while maintaining the overall structural simplicity of the capacitor device.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The top electrode structure is designed as a composite multi-layer system comprising the top electrode, diffusion barrier layer, and capacitor dielectric layer. Each layer is engineered with specific material properties to perform its designated function, creating a composite structure that achieves superior reliability through the synergistic combination of materials with different characteristics.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If removal and cleaning processes are performed on the top electrode, then manufacturing completeness is achieved, but diffusive species cause void formation in the dielectric layer

Engineering Contradiction:

Improvevoid formation preventionVSAvoidremoval and cleaning process

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The diffusion barrier layer serves as a protective intermediary that allows removal and cleaning processes to be performed on the top electrode without exposing the capacitor dielectric layer to harmful diffusive species. The barrier layer enables complete manufacturing processes while preventing the formation of voids in the dielectric layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the top electrode is made conductive, then electrical functionality is achieved, but electrical shorting occurs at high operating voltages

Engineering Contradiction:

Improveelectrical shorting resistanceVSAvoidoperating voltage range

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The diffusion barrier layer acts as an electrical insulator and mediator between the conductive top electrode and the capacitor dielectric layer. This barrier prevents electrical field penetration and charge accumulation at the electrode-dielectric interface, thereby preventing electrical shorting and enabling the capacitor to operate reliably at high voltages.

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 diffusion barrier layer effectively prevents electrical breakdown and top electrode shorting at high operating voltages, enhancing the operating voltage, endurance, and reliability of the MIM capacitor.

Implementation Method 1

a diffusion barrier layer formed using atomic layer deposition and annealing with nitrogen, and a second top electrode layer. This configuration blocks the diffusion of species through the diffusion barrier layer

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 2

a diffusion barrier layer formed using atomic layer deposition and annealing with nitrogen

Methodology Applied

Scientific EffectAnnealing: Annealing

Implementation Method 3

a diffusion barrier layer formed using atomic layer deposition

Methodology Applied

Scientific EffectAtomic layer deposition: Chemical Vapour Deposition

Data Source

PatentUS20250194121A1Diffusion barrier layer in top electrode to increase break down voltage

Publication Date: 2025.06.12 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Various embodiments of the present disclosure are directed towards an integrated chip including a first electrode over a substrate. A dielectric layer is on the first electrode. A second electrode is on the dielectric layer. The second electrode includes a first conductive layer, a diffusion barrier layer on the first conductive layer, and a second conductive layer on the diffusion barrier layer. The first conductive layer comprises a first plurality of grain boundaries continuously extending from a top surface of the dielectric layer in a first direction away from the dielectric layer. The diffusion barrier layer comprises a second plurality of grain boundaries stacked vertically over one another and continuously extending in a second direction approximately perpendicular to the first direction. The second conductive layer comprises a third plurality of grain boundaries extending in the first direction and over the second plurality of grain boundaries.