Amorphous Silicon PVD Deposition on IGZO Metal Oxide

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Solution Overview

Problem

Metal oxide semiconductors, such as indium gallium zinc oxide (IGZO), are susceptible to post-deposition processing deficiencies due to hydrogen-induced oxygen vacancies, leading to unstable semiconductor devices and negative threshold voltages.

Innovation Solution

A physical vapor deposition process is used to deposit an amorphous silicon layer atop metal oxide layers, reducing hydrogen contact and eliminating oxygen vacancies, thereby stabilizing the metal oxide layers and maintaining optimal threshold voltage control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If CVD process is used to deposit amorphous silicon atop metal oxide layers, then deposition is achieved, but bubbling and peeling occur and protection from hydrogen is insufficient

Engineering Contradiction:

Improvestability of metal oxide layerVSAvoiddeposition process quality

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the deposition method from CVD to PVD (physical vapor deposition), fundamentally altering the deposition parameters and mechanism. This parameter change eliminates the bubbling and peeling issues while providing adequate hydrogen protection, resolving the contradiction between manufacturing ease and layer stability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the chemical vapor deposition process with physical vapor deposition, substituting a chemical process with a physical one. This substitution eliminates the chemical reactions that cause bubbling and peeling in CVD, while the PVD process provides the desired hydrogen barrier properties.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If metal oxide layers are exposed to hydrogen during processing, then processing is completed, but oxygen vacancies form making the channel conductive

Engineering Contradiction:

Improveprocessing throughputVSAvoidsemiconductor device stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces an amorphous silicon layer as an intermediary barrier between the metal oxide layer and hydrogen-containing processing environments. This intermediary layer prevents hydrogen from reaching the metal oxide, thereby preventing oxygen vacancy formation while allowing processing to proceed.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The amorphous silicon layer creates an inert barrier environment that protects the metal oxide layer from hydrogen exposure. This inert barrier prevents harmful hydrogen-metal oxide interactions while maintaining processing productivity.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Reliability

If amorphous silicon is deposited to protect metal oxide from hydrogen, then hydrogen protection is improved, but oxygen vacancies still form with CVD deposition

Engineering Contradiction:

Improveprotection from hydrogenVSAvoidoxygen vacancy formation control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces CVD with PVD for amorphous silicon deposition. This substitution is critical because PVD-deposited amorphous silicon provides both hydrogen protection and prevents oxygen vacancy formation, whereas CVD-deposited amorphous silicon fails to prevent oxygen vacancies despite providing hydrogen protection.

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 method effectively reduces oxygen vacancy formation in IGZO layers, enhancing the stability and performance of thin film transistors by preventing hydrogen reactivity and maintaining stable semiconductor device operation.

Implementation Method 1

contacting the layer of indium gallium zinc oxide (IGZO) material with a plasma from a process gas within a processing region of the physical vapor deposition chamber, wherein the process gas comprises an inert gas devoid of hydrogen containing gas to sputter source material from a surface of a target within the processing region of the physical vapor deposition chamber

Methodology Applied

Scientific EffectSputtering: Sputtering

Implementation Method 2

physical vapor deposition (PVD) depositing an amorphous silicon layer atop the indium gallium zinc oxide (IGZO) material

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS11646237B2Methods and apparatuses for depositing amorphous silicon atop metal oxide

Publication Date: 2023.05.09 APPLIED MATERIALS INC

AI summary

In some embodiments, a method of processing a substrate disposed atop a substrate support in a physical vapor deposition process chamber includes: (a) forming a plasma from a process gas within a processing region of the physical vapor deposition chamber, wherein the process gas comprises an inert gas to sputter silicon from a surface of a target within the processing region of the physical vapor deposition chamber; and (b) depositing an amorphous silicon layer atop a first layer on the substrate, wherein the first layer comprises one or more metal oxides of indium (In), gallium (Ga), zinc (Zn), tin (Sn) or combinations thereof.