Oxide Sputtering Target Grain Control for Discharge Stability
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Solution Overview
Problem
Current technologies face challenges in producing oxide semiconductor films for display devices with high carrier mobility while preventing abnormal discharge and cracking during the sputtering process, which affects the stability and efficiency of the production process.
Innovation Solution
An oxide sintered body composed of zinc oxide, indium oxide, and gallium oxide, with specific phase ratios and a relative density of 85% or more, is used to create a sputtering target with a resistivity of 1 Ω·cm or less, which suppresses abnormal discharge and cracking, and enhances the deposition of oxide semiconductor films with high carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sintered density of the target material is increased to prevent cracking, then the structural stability improves, but the grain size increases leading to abnormal discharge
Solution Approach 1:
The patent applies parameter changes by controlling the sintering temperature (900-1100°C) and time (0.5-5 hours) to achieve optimal sintered density (85-95%) while maintaining fine grain structure. This resolves the contradiction by finding the optimal parameter range that prevents cracking without causing grain growth and abnormal discharge
Solution Approach 2:
The patent uses composite oxide materials containing In-Ga-Zn-O as the base composition with additional elements such as Sn, Al, Si, or Ti. This composite structure enhances the target material's mechanical strength and electrical conductivity simultaneously, preventing cracking while suppressing abnormal discharge through improved material properties
2Object-affected harmful factors
If the grain size is refined to suppress abnormal discharge, then the discharge stability improves, but the sintered density decreases leading to target cracking
Solution Approach 1:
The patent employs composite oxide compositions with In-Ga-Zn-O base and additional elements (Sn, Al, Si, Ti) that enable fine grain structure formation while maintaining high sintered density. The composite material structure provides both fine grain boundaries for discharge stability and sufficient density for mechanical integrity
Solution Approach 2:
The patent optimizes sintering parameters (temperature 900-1100°C, time 0.5-5 hours, atmosphere control) to achieve the counterintuitive result of high density with fine grains. This parameter optimization resolves the contradiction by preventing excessive grain growth while ensuring complete densification
3Strength
If the sintering temperature is increased to improve sintered density, then the target strength increases, but the grain growth occurs causing abnormal discharge
Solution Approach 1:
The patent identifies and applies optimal sintering temperature range (900-1100°C) that achieves maximum target strength without excessive grain growth. This parameter optimization resolves the contradiction by finding the temperature window where densification occurs before grain boundary migration becomes dominant
Solution Approach 2:
The composite oxide composition with In-Ga-Zn-O base and additional elements promotes densification at lower temperatures through enhanced diffusion and phase formation, preventing the need for high-temperature sintering that would cause grain growth and abnormal discharge
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 effectively suppresses abnormal discharge and cracking, ensuring stable deposition of oxide semiconductor films with high carrier mobility, improving the productivity and cost-effectiveness of the sputtering process.
Implementation Method 1
a sputtering method has been preferably employed, in which a sputtering target (hereinafter sometimes referred to as 'target material') composed of the same materials as the film is subjected to sputtering
Implementation Method 2
an oxide sintered body obtained by mixing and sintering a zinc oxide; an indium oxide; a gallium oxide; and a tin oxide
Data Source
AI summary
An oxide sintered body which is obtained by mixing and sintering zinc oxide, indium oxide, gallium oxide and tin oxide. The relative density of the oxide sintered body is 85% or more and the average grain size of crystal grains observed on the surface of the oxide sintered body is less than 10 μm. X-ray diffraction of the oxide sintered body shows that a Zn2SnO4 phase and an InGaZnO4 phase are the main phases and that an InGaZn2O5 phase is contained in an amount of 3 volume % or less.