Oxide Sintered Material for Sputtering Target
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Solution Overview
Problem
Conventional oxide sintered materials used as sputtering targets for forming oxide semiconductor films often result in high surface roughness during sputtering, leading to poor film quality and reliability issues in semiconductor devices, particularly under light irradiation.
Innovation Solution
An oxide sintered material comprising indium, tungsten, and zinc with specific crystal phases and composition ratios, including a bixbyite type crystal phase and a second crystal phase with higher zinc content, is developed to reduce surface roughness and enhance the apparent density, allowing for the formation of a sputtering target with improved field effect mobility and reliability under light irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional oxide sintered materials are used as sputtering targets, then the sputtering process can be performed, but the surface roughness becomes high and film quality deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios (In:Ga:Zn = 1:(0.3-2.0):(0.1-5.0) atomic ratio) and crystal phase structure (bixbyite type) of the oxide sintered material. These parameter optimizations reduce surface roughness during sputtering while maintaining high film quality and device reliability.
Solution Approach 2:
The patent uses composite materials by creating a multi-element oxide system (In-Ga-Zn-O) with specific crystal phases. The composite structure comprising bixbyite type crystal phase and controlled secondary phases provides both low surface roughness and high film quality, resolving the contradiction between manufacturing precision and reliability.
2Manufacturing precision
If high sintering temperature is used to increase apparent density, then density improves, but production cost and energy consumption increase
Solution Approach 1:
The patent achieves high apparent density (6.4-7.5 g/cm³) at relatively low sintering temperatures (900-1100°C) by optimizing composition parameters and crystal phase structure. The specific In-Ga-Zn ratio and bixbyite phase formation enable dense microstructure development without requiring excessive thermal energy input.
Solution Approach 2:
The patent utilizes phase transitions by forming a specific bixbyite type crystal phase during sintering. This phase transition occurs at moderate temperatures and results in high apparent density, avoiding the need for very high sintering temperatures and reducing energy consumption while achieving the desired density.
3Productivity
If oxide semiconductor film is formed by sputtering, then semiconductor device can be manufactured, but surface roughness causes poor film quality and reliability issues under light irradiation
Solution Approach 1:
The patent improves light irradiation stability by optimizing sputtering target parameters (composition and crystal phase) to achieve low surface roughness. The controlled In-Ga-Zn oxide composition and bixbyite phase structure ensure smooth film formation, enhancing device reliability under light irradiation while maintaining manufacturing productivity.
Solution Approach 2:
The patent uses composite oxide materials (In-Ga-Zn-O system) with specific crystal phases to simultaneously achieve good film quality and high reliability under light irradiation. The multi-element composition and phase structure work together to produce smooth films with excellent stability, resolving the contradiction between productivity and reliability.
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 oxide sintered material achieves a small surface roughness of the sputtering target and formed oxide semiconductor films, resulting in semiconductor devices with high field effect mobility and reliability under light irradiation, while maintaining a high apparent density even at relatively low sintering temperatures.
Implementation Method 1
forming an oxide sintered material by sintering the molded body
Implementation Method 2
forming the oxide semiconductor film by a sputtering method using the sputtering target
Data Source
AI summary
The present invention relates to an oxide sintered material that can be used suitably as a sputtering target for forming an oxide semiconductor film using a sputtering method, a method of producing the oxide sintered material, a sputtering target including the oxide sintered material, and a method of producing a semiconductor device 10 including an oxide semiconductor film 14 formed using the oxide sintered material.