InGaO3(ZnO) Sputtering Target for Oxide Semiconductor
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Solution Overview
Problem
Conventional sputtering targets for oxide semiconductor thin film transistors face issues with reproducibility, mobility, ON-OFF ratio, and film-forming speed due to shifts in composition ratios and the presence of crystalline phases other than InGaO3(ZnO), leading to variations in transistor properties and industrialization challenges.
Innovation Solution
A sputtering target with a homologous crystal structure represented by InGaO3(ZnO) is developed, where the composition ratio of In and Ga is maintained within specific ranges, and sintered under controlled conditions to minimize peaks at 2θ=62-63 degrees, ensuring uniform bulk resistance and reduced particle formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sputtering targets with multi-crystalline structure are used, then film formation is possible, but composition ratio shifts and crystalline phases other than InGaO3(ZnO) form, leading to low reproducibility and varied transistor properties
Solution Approach 1:
The patent applies parameter changes by precisely controlling the atomic ratios of In, Ga, and Zn within specific ranges (In: 0.3-0.6, Ga: 0.1-0.3, Zn: 0.1-0.4) and optimizing sintering conditions (temperature: 1000-1500°C, time: 1-48 hours, atmosphere: oxygen or air) to obtain a homogeneous oxide sintered body with minimal unwanted crystalline phases, thereby achieving stable composition ratios and high reproducibility in transistor properties
Solution Approach 2:
The patent uses composite materials by creating an oxide sintered body composed of multiple metal oxides (In2O3, Ga2O3, ZnO) in specific composite ratios that form a homogeneous mixture with controlled crystalline structure, minimizing the formation of unwanted crystalline phases like Ga2O3, ZnGa2O4, In2O3(ZnO)3, and InGaO3, thereby achieving both compositional precision and high reproducibility
2Productivity
If sputtering is performed with conventional targets, then thin films can be formed, but abnormal discharges occur and film-forming speed decreases, reducing productivity
Solution Approach 1:
The patent applies parameter changes by optimizing the oxide content (40-80 wt%) and metal element ratios in the sputtering target, along with controlling sintering parameters (temperature, time, atmosphere), to create a homogeneous oxide sintered body that prevents abnormal discharges during sputtering, thereby enabling stable and high-speed film formation without interruptions
Solution Approach 2:
The patent converts the potential harm of unwanted crystalline phases (Ga2O3, ZnGa2O4, etc.) into benefit by establishing specific compositional ranges and sintering conditions that suppress their formation. By controlling the oxide content and metal ratios, the patent transforms the sintering process into a method that produces a homogeneous structure free from harmful phases, enabling stable sputtering operation
3Reliability
If oxide semiconductor films are formed with conventional targets, then films can be produced, but transistor properties such as mobility and ON-OFF ratio are degraded due to composition variations
Solution Approach 1:
The patent applies parameter changes by precisely defining and controlling the atomic ratios of In (0.3-0.6), Ga (0.1-0.3), and Zn (0.1-0.4) in the oxide sintered body, along with optimizing oxide content (40-80 wt%) and sintering conditions. This precise parameter control ensures uniform oxide composition in the resulting thin films, leading to consistent transistor properties including mobility and ON-OFF ratio across different batches
Solution Approach 2:
The patent uses composite materials by creating a homogeneous oxide sintered body from carefully proportioned metal oxides (In2O3, Ga2O3, ZnO) with controlled crystalline structure. This composite approach ensures uniform distribution of metal elements in the sputtered films, preventing composition variations that would degrade transistor performance, thereby achieving reliable and consistent transistor properties
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 solution provides high reproducibility and improved transistor properties, including mobility and ON-OFF ratio, while preventing abnormal discharges and enhancing film-forming speed, thus addressing the limitations of existing targets.
Implementation Method 1
a sputtering target for an oxide semi-conductor, comprising InGaO3(ZnO) crystal phase
Implementation Method 2
sintered under controlled conditions to minimize peaks at 2θ=62-63 degrees
Data Source
AI summary
Disclosed is a sputtering target for an oxide semiconductor, comprising In, Ga, and Zn. Also disclosed are a process for producing the sputtering target, a thin film of an oxide semiconductor using a sputtering target, and a method for thin-film transistor formation. The sputtering target comprises an oxide sintered compact containing a compound having a homologous crystal structure represented by InGaO3(ZnO) and exhibits such an X-ray diffraction pattern that the proportion of peaks at 2θ=62 to 63 degrees to the maximum peak of InGaO3(ZnO) is not more than 3%.