FeRAM Hydrogen Barrier Stack for Metal-Oxide Channel Stability

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Solution Overview

Problem

Metal-oxide channel layers in ferroelectric random access memory (FeRAM) structures are susceptible to hydrogen contamination, leading to increased charge carrier concentration, off-current leakage, and instability issues such as PBTI and NBTI, which can render the FeRAM structure non-operational.

Innovation Solution

A multiple-layer hydrogen barrier stack comprising a hydrogen absorption layer and a hydrogen blocking layer is introduced between the FeRAM structure and conductive structures in the interconnect structure to minimize and prevent hydrogen diffusion, using materials like ruthenium, titanium nitride, and metal-oxide semiconductor materials to absorb and block hydrogen.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal-oxide channel layers are used in FeRAM structures, then device functionality is achieved, but hydrogen contamination increases charge carrier concentration and causes instability

Engineering Contradiction:

ImproveFeRAM operational stabilityVSAvoidhydrogen contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A hydrogen barrier stack comprising multiple layers (including titanium nitride, ruthenium, and aluminum oxide) is introduced as an intermediary between the metal-oxide channel layer and conductive structures. This barrier stack absorbs and blocks hydrogen diffusion, preventing hydrogen contamination of the channel layer while maintaining device functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The hydrogen barrier utilizes composite material structures combining different materials with complementary properties: titanium nitride for hydrogen absorption, ruthenium for hydrogen blocking, and aluminum oxide for additional barrier protection. This composite approach effectively prevents hydrogen contamination while maintaining device performance.

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If conductive structures are integrated with FeRAM, then interconnect functionality is achieved, but hydrogen diffusion increases off-current leakage

Engineering Contradiction:

Improveinterconnect functionalityVSAvoidoff-current leakage

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The hydrogen barrier stack serves as an intermediary layer between conductive structures and the FeRAM channel layer, blocking hydrogen diffusion pathways. This prevents hydrogen from reaching the channel layer and causing off-current leakage, while allowing electrical interconnect functionality to operate normally through the barrier structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If hydrogen barrier stack is added, then hydrogen diffusion is prevented, but device complexity increases

Engineering Contradiction:

Improvehydrogen barrier effectivenessVSAvoidlayer structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The hydrogen barrier is segmented into multiple functional layers, each with specific thicknesses and material compositions optimized for hydrogen blocking. This segmentation allows each layer to perform its specific function efficiently while maintaining overall device performance and manageability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The hydrogen barrier stack serves multiple functions simultaneously: hydrogen absorption, hydrogen blocking, electrical isolation, and structural support. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving reliable hydrogen protection.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 hydrogen barrier stack reduces charge carrier concentration, lowers off-current leakage, and prevents the FeRAM structure from becoming non-operational by minimizing hydrogen diffusion, thereby enhancing the reliability and stability of the FeRAM.

Implementation Method 1

The hydrogen absorption layer may include one or more metal-oxide-containing materials or one or more metal-oxide semiconductor materials that absorb hydrogen

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

The hydrogen blocking layer blocks or resists diffusion of hydrogen through the conductive structures into the FeRAM structure

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS20250240973A1Ferroelectric non-volatile memory and methods of formation

Publication Date: 2025.07.24 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A multiple-layer hydrogen barrier stack may be included between a non-volatile memory structure and conductive structures in an interconnect structure in a semiconductor device. The multiple-layer hydrogen barrier stack may minimize and/or prevent hydrogen diffusion into one or more layers of the non-volatile memory structure such as a metal-oxide channel of the non-volatile memory structure. The multiple-layer hydrogen barrier stack may include a hydrogen absorption layer and a hydrogen blocking layer on the hydrogen absorption layer. The hydrogen blocking layer blocks or resists diffusion of hydrogen through the conductive structures into the non-volatile memory structure. The hydrogen absorption layer may absorb any hydrogen atoms that might diffuse through the hydrogen blocking layer.