Segmented Sputtering Target for Oxide Transistor Reliability
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Solution Overview
Problem
Transistors with amorphous oxide active layers, such as In—Zn—Ga—O-based oxides, suffer from low on-state current and poor reliability in electrical characteristics.
Innovation Solution
A sputtering target with distinct regions of different metal oxides, including indium and zinc-based oxides, is used to form a semiconductor device, where each region has a crystal grain structure and a crystal grain boundary, enhancing electrical characteristics and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an amorphous oxide is used as the active layer of a transistor, then the manufacturing process is simplified, but the on-state current and reliability deteriorate
Solution Approach 1:
The invention changes the structural parameter of the metal oxide from amorphous to crystalline state. By controlling the sputtering conditions and post-treatment processes, the metal oxide layer is transformed into a crystalline structure with specific grain sizes (5 nm to 10 μm), which significantly improves carrier mobility and transistor reliability while maintaining the simplicity of the sputtering deposition process
Solution Approach 2:
The invention uses a composite structure consisting of multiple regions with different metal oxide compositions (first metal oxide containing element M1, second metal oxide containing indium and element M2). This composite approach allows optimization of different regions for different functions, achieving both high on-state current and good reliability
2Device complexity
If a single-phase metal oxide is used in the sputtering target, then the target structure is simplified, but the electrical characteristics and reliability of the resulting semiconductor device deteriorate
Solution Approach 1:
The sputtering target is divided into multiple distinct regions, each containing different metal oxide compositions. The first region contains a first metal oxide with element M1, while the second region contains a second metal oxide with indium and element M2. These regions are separated by crystal grain boundaries, creating a segmented structure that improves the electrical characteristics and reliability of the resulting semiconductor device
Solution Approach 2:
Different regions of the sputtering target are given different local compositions and crystal structures. Each region is optimized for specific properties, with the first region containing element M1 for certain electrical characteristics and the second region containing indium and element M2 for other complementary properties, achieving overall device optimization through local differentiation
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 approach results in semiconductor devices with improved electrical characteristics and reliability by optimizing the composition and structure of the metal oxide layers, specifically increasing field-effect mobility and reducing off-state current.
Implementation Method 1
Sputtering target and method for forming sputtering target
Data Source
AI summary
A novel sputtering target is provided. The sputtering target includes a first region and a second region. The first region contains a first metal oxide containing an element M1 (the element M1 is one or more elements selected from Al, Ga, Si, Mg, Zr, and B). The second region contains a second metal oxide containing indium and zinc. The first region and the second region are separated from each other. Each of the first region and the second region is a crystal grain. A crystal grain boundary is observed between the first region and the second region. The diameter of each of the first region and the second region is greater than or equal to 5 nm and less than or equal to 10 μm.