MIM Capacitor Interfacial Layer for Breakdown and Leakage Control

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Solution Overview

Problem

The formation of a native oxide layer on the top surface of a titanium nitride bottom electrode in MIM capacitors leads to increased roughness, dielectric breakdown, and reduced performance due to charge traps, leakage current, and parasitic capacitance, exacerbated by high voltages and temperatures.

Innovation Solution

A plasma treatment process converts the native oxide layer into a conductive interfacial layer, such as titanium oxynitride, which enhances adhesion and smooths the electrode surface, reducing delamination and parasitic capacitance, and acts as a diffusion barrier to prevent oxidant penetration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a native oxide layer forms on the titanium nitride bottom electrode, then the electrode surface is naturally protected, but the surface roughness increases and dielectric breakdown occurs

Engineering Contradiction:

Improvedielectric breakdown resistanceVSAvoidsurface roughness

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies plasma treatment to change the physical and chemical parameters of the native oxide layer, converting it from a high-resistivity, rough surface layer into a conductive, smooth interfacial layer with controlled composition (titanium oxynitride), thereby resolving the contradiction between protection and surface quality

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful native oxide layer, which causes roughness and breakdown, into a beneficial conductive interfacial layer through plasma treatment. The same oxide that initially caused problems becomes the foundation for improved adhesion and reduced parasitic capacitance after nitrogen incorporation

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If a native oxide layer is present on the bottom electrode, then oxidation protection is provided, but charge traps and leakage current increase

Engineering Contradiction:

Improveoxidation protectionVSAvoidleakage current

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

Plasma treatment changes the electrical parameters of the oxide layer by incorporating nitrogen, transforming it from a high-resistivity layer with charge traps into a conductive interfacial layer, thereby eliminating leakage current while maintaining oxidation protection

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The plasma treatment process acts as an intermediary that modifies the oxide layer properties, introducing nitrogen as a mediating element that converts the harmful oxide into a beneficial conductive interfacial layer

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stability of the object's composition

If a native oxide layer forms on the electrode, then natural oxidation occurs, but parasitic capacitance and delamination increase

Engineering Contradiction:

Improveoxidation stabilityVSAvoidadhesion strength

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

Plasma treatment changes the compositional parameters of the oxide layer by incorporating nitrogen, creating a titanium oxynitride interfacial layer that maintains oxidation stability while improving adhesion and reducing delamination

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The plasma treatment creates a composite interfacial layer combining titanium, oxygen, and nitrogen elements, where the composite structure provides both oxidation stability and improved adhesion properties that neither pure oxide nor pure metal could achieve alone

Inventive Principle:

Principle #40Composite materials

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 interfacial layer improves dielectric breakdown resistance, reduces leakage current, and maintains capacitance uniformity, thereby enhancing the reliability and performance of MIM capacitors under operating conditions.

Implementation Method 1

generating plasma from nitrogen oxide; exposing the native oxide layer to the plasma

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 2

nitrogen and oxygen diffuse into the native oxide layer and the bottom electrode layer

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS20250344418A1Method to reduce breakdown failure in a MIM capacitor

Publication Date: 2025.11.06 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Various embodiments of the present application are directed towards a method for forming a metal-insulator-metal (MIM) capacitor comprising an enhanced interfacial layer to reduce breakdown failure. In some embodiments, a bottom electrode layer is deposited over a substrate. A native oxide layer is formed on a top surface of the bottom electrode layer and has a first adhesion strength with the top surface. A plasma treatment process is performed to replace the native oxide layer with an interfacial layer. The interfacial layer is conductive and has a second adhesion strength with the top surface of the bottom electrode layer, and the second adhesion strength is greater than the first adhesion strength. An insulator layer is deposited on the interfacial layer. A top electrode layer is deposited on the insulator layer. The top and bottom electrode layers, the insulator layer, and the interfacial layer are patterned to form a MIM capacitor.