Graphene Barrier Layer for Semiconductor Contact Resistance Reduction

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Solution Overview

Problem

Conventional barrier layers in semiconductor devices, such as titanium and titanium nitride layers, have high thickness and Schottky barriers, leading to increased contact resistance, which is not effectively reduced by existing methods.

Innovation Solution

A method for forming a graphene barrier layer using a substrate processing system, where a titanium-containing layer is nucleated with an unsaturated hydrocarbon gas and then a graphene layer is formed using a saturated hydrocarbon gas, employing plasma-enhanced atomic layer deposition to reduce contact resistance and enhance adhesion to tungsten layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional titanium layer/titanium nitride layer barrier layer is formed with thickness of 50 Å or more, then the barrier layer can prevent stress, silicon diffusion and electron transfer, but the large thickness causes high Schottky barrier and increased contact resistance

Engineering Contradiction:

Improvebarrier functionVSAvoidcontact resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the conventional thick barrier layer (50 Å or more) with an ultra-thin graphene layer (single-atom thickness), utilizing the thin film principle to achieve barrier functionality with minimal thickness. The graphene layer provides effective barrier properties against stress, silicon diffusion, and electron transfer while maintaining low contact resistance due to its atomic-scale thickness and excellent electrical conductivity.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the material parameter from conventional metals (titanium, titanium nitride) to graphene, fundamentally altering the barrier layer's electrical and mechanical properties. This material substitution enables the barrier layer to simultaneously achieve high barrier performance and low contact resistance by exploiting graphene's unique electronic structure and high charge mobility.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If graphene is used as a barrier layer to reduce contact resistance, then contact resistance is reduced and adhesion to tungsten is improved, but conventional methods lack sufficient studies on forming such barrier layers

Engineering Contradiction:

Improvecontact resistanceVSAvoidmanufacturing method

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent replaces conventional physical deposition methods with plasma-enhanced chemical vapor deposition (PECVD) to form graphene barrier layers. This substitution enables precise control over graphene formation, achieving uniform ultra-thin layers with excellent adhesion to tungsten interconnects while maintaining low contact resistance, thereby solving the manufacturing challenge of forming graphene-based barrier layers.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 graphene barrier layer achieves reduced contact resistance and improved electrical properties by forming a thin layer with excellent adhesion to tungsten, outperforming traditional titanium and titanium nitride layers in semiconductor devices.

Implementation Method 1

inducing nucleation on the titanium-containing layer by supplying a first reactant gas including a unsaturated hydrocarbon into the chamber

Methodology Applied

Scientific EffectNucleation: Nucleation

Implementation Method 2

forming a graphene layer on the titanium-containing layer by supplying a second reactant gas containing a saturated hydrocarbon into the chamber

Methodology Applied

Scientific EffectPlasma-enhanced atomic layer deposition: Plasma Enhanced Chemical Vapour Deposition

Implementation Method 3

each of the first and second reactant gases may be ionized into plasma before being supplied into the chamber of the substrate processing system, and the graphene layer may be formed by plasma-enhanced atomic layer deposition (PEALD) using the ionized first and second reactant gases

Methodology Applied

Scientific EffectPlasma: Plasma

Data Source

PatentUS20230081962A1Method for forming graphene barrier layer for semiconductor device and contact structure formed by the same

Publication Date: 2023.03.16 WONIK IPS CO LTD

AI summary

Various embodiments generally relate to a method for forming a graphene barrier layer for a semiconductor device, and more particularly, to a method of forming a barrier thin film including a graphene layer capable of reducing the contact resistance of a metal interconnect. A method for forming a graphene barrier layer according to an embodiment includes: loading a substrate, which has a titanium-containing layer formed thereon, in a chamber of a substrate processing system, the chamber having a processing space formed therein; inducing nucleation on the titanium-containing layer by supplying a first reactant gas including a unsaturated hydrocarbon into the chamber; and forming a graphene layer on the titanium-containing layer by supplying a second reactant gas including a saturated hydrocarbon into the chamber.