Oxide Semiconductor Transistor Electrode Schottky Barriers
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Solution Overview
Problem
Forming both n-channel and p-channel transistors using the same substrate with oxide semiconductors is challenging due to differences in their conduction mechanisms, making it difficult to achieve efficient and productive manufacturing processes.
Innovation Solution
The solution involves creating distinct structures for n-channel and p-channel transistors using oxide semiconductors, with different electrode materials and stacked-layer structures for each, allowing for the formation of Schottky barriers that optimize carrier injection properties and reduce the number of manufacturing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the same oxide semiconductor material is used for both n-channel and p-channel transistors, then material consistency is achieved, but the conduction mechanisms differ making it difficult to form both transistor types effectively
Solution Approach 1:
The patent applies local quality by using the same oxide semiconductor material (In-Ga-Zn-based oxide) for both n-channel and p-channel transistors but forming different Schottky barrier structures at the electrode-semiconductor interfaces. The n-channel transistor uses a first electrode material with a first work function to form a first Schottky barrier, while the p-channel transistor uses a second electrode material with a second work function to form a second Schottky barrier. This local differentiation in electrode materials allows each transistor type to have optimized carrier injection properties while maintaining material consistency in the channel layer.
Solution Approach 2:
The patent changes the work function parameter of the electrode materials to create different Schottky barrier characteristics. By selecting electrode materials with appropriate work functions (first work function for n-channel, second work function for p-channel), the energy band alignment at the electrode-semiconductor interface is optimized for each transistor type. This parameter change enables compatible conduction mechanisms for both n-channel and p-channel transistors using the same oxide semiconductor material.
2Reliability
If different structures are created for n-channel and p-channel transistors, then transistor characteristics are improved, but manufacturing complexity increases
Solution Approach 1:
The patent differentiates only the electrode material composition and Schottky barrier structure between n-channel and p-channel transistors, while keeping the oxide semiconductor channel layer material the same. This localized structural differentiation optimizes carrier injection for each transistor type without requiring complete structural redesign, thus improving transistor characteristics while limiting complexity increase to specific regions only.
Solution Approach 2:
The patent uses a universal oxide semiconductor material (In-Ga-Zn-based oxide) that can serve as the channel layer for both n-channel and p-channel transistors. This multi-functional material approach allows the same semiconductor layer to support both transistor types, reducing the need for separate material systems and simplifying the overall device structure while still allowing for differentiated electrode configurations.
3Reliability
If multiple manufacturing steps are used to form different electrode structures, then transistor performance is optimized, but productivity decreases
Solution Approach 1:
The patent forms the gate electrode and gate insulating layer structure before forming the oxide semiconductor layer and source/drain electrodes. This preliminary structuring establishes the foundation for subsequent Schottky barrier formation, allowing optimized electrode materials to be deposited in later steps with clear knowledge of the existing structure, thereby streamlining the manufacturing process while achieving performance optimization.
Solution Approach 2:
The patent optimizes transistor performance by changing the work function parameter of electrode materials to create appropriate Schottky barriers. This parameter-based optimization approach allows performance tuning through material selection rather than complex multi-step processing, improving transistor characteristics while maintaining manufacturing efficiency by focusing changes on material properties rather than process complexity.
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
This approach enables the production of transistors with improved characteristics, reduces manufacturing costs, and increases productivity by minimizing the number of masks and steps required, while enabling the formation of CMOS circuits with enhanced performance.
Implementation Method 1
creating distinct structures for n-channel and p-channel transistors using oxide semiconductors, with different electrode materials and stacked-layer structures for each, allowing for the formation of Schottky barriers that optimize carrier injection properties
Data Source
AI summary
An object is to provide an n-channel transistor and a p-channel transistor having a preferred structure using an oxide semiconductor. A first source or drain electrode which is electrically connected to a first oxide semiconductor layer and is formed using a stacked-layer structure including a first conductive layer containing a first material and a second conductive layer containing a second material, and a second source or drain electrode which is electrically connected to a second oxide semiconductor layer and is formed using a stacked-layer structure including a third conductive layer containing the first material and a fourth conductive layer containing the second material are included. The first oxide semiconductor layer is in contact with the first conductive layer of the first source or drain electrode, and the second oxide semiconductor layer is in contact with the third and the fourth conductive layers of the second source or drain electrode.