Oxide Semiconductor Device with Segmented Channel Region
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving low defect states in semiconductor layers, leading to unstable electric characteristics, high off-state current, and reduced field-effect mobility, which complicates the manufacturing process and yields.
Innovation Solution
A semiconductor device is developed with a region having a low density of defect states, achieved by forming a mixed region between two oxide semiconductor layers with different atomic ratios and utilizing chemical reactions to modify the quality of these layers, thereby reducing impurity entry and enhancing the energy gap, which protects the channel region and improves transistor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single oxide semiconductor layer is used, then the manufacturing process is simple, but the density of defect states is high leading to unstable electric characteristics
Solution Approach 1:
The semiconductor layer is divided into two distinct oxide semiconductor layers (first and second layers) with different atomic ratios. The first layer has a lower atomic ratio of In to Ga/Zn while the second layer has a higher atomic ratio, creating a gradient structure that reduces defect states at the interface and improves overall device reliability.
Solution Approach 2:
Different regions of the semiconductor structure are assigned different compositional qualities. The first oxide semiconductor layer near the gate insulating film has a composition optimized for interface quality and low defect states, while the second layer has a composition optimized for electrical performance, creating local quality variations that solve the contradiction.
2Reliability
If high-temperature heat treatment or laser light treatment is applied to form polycrystalline silicon film, then field-effect mobility is improved, but the manufacturing process complexity and number of steps increase
Solution Approach 1:
The invention changes the compositional parameters of the oxide semiconductor layers, specifically the atomic ratios of In, Ga, and Zn. By optimizing these parameters, the material inherently achieves high field-effect mobility without requiring post-deposition high-temperature heat treatment or laser light treatment, thus maintaining manufacturing efficiency.
Solution Approach 2:
The invention uses composite oxide semiconductor materials combining multiple elements (In, Ga, Zn, and oxygen) in specific ratios. This composite material structure provides both the desired high field-effect mobility and compatibility with existing manufacturing processes, avoiding the need for additional complex treatment steps.
3Reliability
If the atomic ratio of In to Ga/Zn is increased, then the energy gap is enhanced, but the carrier density increases leading to higher off-state current
Solution Approach 1:
The semiconductor structure is segmented into two layers with different In to Ga/Zn atomic ratios. The first layer has a lower ratio that maintains appropriate carrier density and low off-state current, while the second layer has a higher ratio that provides enhanced energy gap, thus distributing the functional requirements across different segments.
Solution Approach 2:
Different local regions (layers) are assigned different compositional qualities regarding In content. The region closer to the gate insulating film has lower In content for electrical stability, while the upper region has higher In content for energy gap enhancement, optimizing both parameters simultaneously.
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 a semiconductor device with stable electric characteristics, low off-state current, high field-effect mobility, and a reduced number of manufacturing steps, enhancing yield and performance.
Implementation Method 1
utilizing chemical reactions to modify the quality of these layers
Data Source
AI summary
In a semiconductor device, a region where a channel is formed is protected. In a semiconductor device, a region protecting a region where a channel is formed is provided in a semiconductor layer. In a semiconductor device, a layer protecting a region where a channel is formed is provided. In a semiconductor device, a region and/or a layer protecting a region where a channel is formed have/has a low density of defect states. In a semiconductor device, a region where a channel is formed has a low density of defect states.