InGaAlO Crystalline Compound for Stable Sputtering and High Mobility

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Solution Overview

Problem

There is a demand for a higher-quality thin-film transistor (TFT) with high process durability and high carrier mobility, and existing materials struggle to achieve stable sputtering and durability across various processes such as CVD.

Innovation Solution

A crystalline structure compound represented by the composition formula (InxGayAlz)2O3, with specific diffraction peaks and atomic ratios, is used to form an oxide sintered body, sputtering target, and thin films, enabling high process durability and mobility in TFTs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional oxide semiconductor materials are used for TFT fabrication, then the manufacturing process can be completed, but the process durability is insufficient and carrier mobility is limited

Engineering Contradiction:

Improveprocess durabilityVSAvoidcarrier mobility

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent employs a composite oxide semiconductor material system consisting of In-Ga-Al-O with specific compositional ratios (In: 40-70 at%, Ga: 10-30 at%, Al: 5-20 at%). This composite material approach combines multiple metal elements to achieve synergistic effects that simultaneously improve process durability through enhanced material stability and increase carrier mobility through optimized electronic structure, directly resolving the technical contradiction between reliability and productivity

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If sputtering method is used to form oxide semiconductor films, then excellent in-plane uniformity and component composition are achieved, but stable sputtering is difficult to maintain with existing materials

Engineering Contradiction:

Improvein-plane uniformityVSAvoidsputtering stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the compositional parameters of the In-Ga-Al-O system within specific ranges (In: 40-70 at%, Ga: 10-30 at%, Al: 5-20 at%). This compositional optimization modifies the material properties to achieve both stable sputtering deposition and excellent in-plane uniformity, resolving the contradiction between manufacturing precision and process reliability

Inventive Principle:

Principle #35Parameter changes

3Productivity

If higher carrier mobility is achieved in oxide semiconductors, then next generation display performance is improved, but material stability and process durability are compromised

Engineering Contradiction:

Improvecarrier mobilityVSAvoidmaterial stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent uses a composite In-Ga-Al-O semiconductor material where the specific combination of metal elements creates a stable crystal structure that maintains material stability while the optimized compositional ratios enhance carrier mobility. The multi-element composite structure provides both the stability needed for material integrity and the electronic properties required for high mobility, resolving the contradiction between productivity and compositional stability

Inventive Principle:

Principle #40Composite materials

4Ease of manufacture

If existing oxide sintered bodies are used for sputtering targets, then target fabrication is possible, but high process durability and mobility cannot be simultaneously achieved

Engineering Contradiction:

Improvetarget fabricationVSAvoidprocess durability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes by optimizing the compositional parameters of the oxide sintered body within specific ranges (In: 40-70 at%, Ga: 10-30 at%, Al: 5-20 at%). This compositional control enables straightforward target fabrication while simultaneously achieving high process durability and carrier mobility, resolving the contradiction between ease of manufacture and reliability

Inventive Principle:

Principle #35Parameter changes

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 crystalline structure compound achieves stable sputtering and high process durability, along with high mobility in TFTs, by forming a sputtering target and thin films with precise composition and structural properties.

Implementation Method 1

A sputtering method, through which a sputtering target is sputtered, is preferably used for formation of the above oxide semiconductor (film)

Methodology Applied

Scientific EffectSputtering: Sputtering

Implementation Method 2

having diffraction peaks respectively in below-defined ranges (A) to (K) of an incidence angle (2θ) observed by X-ray (Cu—K α ray) diffraction measurement

Methodology Applied

Scientific EffectX-ray diffraction: X-Ray

Data Source

PatentUS20210343876A1Crystal structure compound, oxide sintered body, sputtering target, crystalline oxide thin film, amorphous oxide thin film, thin film transistor and electronic equipment

Publication Date: 2021.11.04 IDEMITSU KOSAN CO LTD

AI summary

A crystalline structure compound A is represented by a composition formula (2) and has having diffraction peaks respectively in below-defined ranges (A) to (K) of an incidence angle observed by X-ray diffraction measurement.(InxGayAlz)2O3 (2)In the formula (2), 0.47≤x≤0.53, 0.17≤y≤0.43, 0.07≤z≤0.33, and x+y+z=1.31° to 34° (A), 36° to 39° (B), 30° to 32° (C), 51° to 53° (D), 53° to 56° (E), 62° to 66° (F), 9° to 11° (G), 19° to 21° (H), 42° to 45° (I), 8° to 10° (J), and 17° to 19° (K).