Oxide Sintered Compact for Stable DC Sputtering
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Solution Overview
Problem
Sputtering targets and oxide sintered compacts for producing oxide semiconductor films in display devices face challenges in achieving superior electroconductivity, high relative densities, and stable direct-current discharge, while also being cost-effective and suitable for mass production on large-sized substrates.
Innovation Solution
An oxide sintered compact is created by mixing and sintering zinc oxide, tin oxide, and indium oxide, with a Zn2SnO4 phase as the main phase, including an In/In2O3—ZnSnO3 solid solution and no ZnxInyOz phase, optimized for specific metal content ratios and heat treatment conditions to achieve high relative density and low resistivity, enabling stable direct-current sputtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If indium content is reduced in ITO to lower material cost, then material cost decreases, but relative density and electroconductivity deteriorate
Solution Approach 1:
The patent changes the compositional parameters by introducing zinc and tin oxides in specific ratios to replace indium oxide, transforming the material system from ITO to ZTO while maintaining electroconductivity and improving density
Solution Approach 2:
The patent creates a composite oxide semiconductor material comprising ZnO, SnO2, and In2O3 in a specific compositional ratio (Zn: 40-70 at%, Sn: 10-50 at%, In: 1-20 at%), where the combination of multiple oxides achieves superior properties compared to individual components
2Productivity
If conventional sputtering targets are used for oxide semiconductor deposition, then deposition can be performed, but abnormal discharge and cracking occur during sputtering
Solution Approach 1:
The patent optimizes the compositional ratio parameters of ZnO, SnO2, and In2O3 to specific ranges, which fundamentally changes the material properties to eliminate abnormal discharge and cracking while maintaining sputtering deposition capability
Solution Approach 2:
The patent creates a material with non-uniform phase distribution where Zn2SnO4 spinel phase coexists with In-Zn-Sn-O solid solution, providing different functional regions that collectively prevent discharge instability and cracking
3Productivity
If RF sputtering is used for deposition, then oxide semiconductor films can be deposited, but deposition speed is slow reducing productivity
Solution Approach 1:
The patent changes the electrical parameter of the sputtering target by optimizing composition and density, enabling the transition from RF to DC sputtering mode, which dramatically increases deposition speed while maintaining film quality through controlled compositional ratios
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 resulting sputtering targets exhibit low resistivity, high relative density, and excellent in-plane uniformity, allowing for high-speed and stable deposition of oxide semiconductor films with satisfactory carrier mobility, reducing material costs and improving productivity.
Implementation Method 1
mixing and sintering powders of zinc oxide, tin oxide, and indium oxide
Implementation Method 2
deposition of such an oxide semiconductor (film) preferably employs sputtering, in which a sputtering target including the same materials as the film is subjected to sputtering
Data Source
AI summary
This oxide sintered compact is obtained by mixing and sintering powders of zinc oxide, tin oxide and indium oxide. As determined by X-ray diffractometry of this oxide sintered compact, the oxide sintered compact has a Zn2SnO4 phase as the main phase and contains an In/In2O3—ZnSnO3 solid solution wherein In and/or In2O3 is solid-solved in ZnSnO3, but a ZnxInyOz phase (wherein x, y and z each represents an arbitrary positive integer) is not detected. Consequently, the present invention was able to provide an oxide sintered compact which is suitable for use in the production of an oxide semiconductor film for display devices and has both high electrical conductivity and high relative density. The oxide sintered compact is capable of forming an oxide semiconductor film that has high carrier mobility.