Oxide Semiconductor Transistor with Intermediary Films
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving reliable transistor performance due to impurity-induced carrier generation and crystal defects, particularly in oxide semiconductor films used in display devices, which affect the reliability and efficiency of the devices.
Innovation Solution
The semiconductor device incorporates a gate wiring, active layer, gate insulating film, and semiconductor films with oxide semiconductors, including electron-trapping films to manage parasitic capacitance and impurity ingress, and a manufacturing method that involves chemical vapor deposition and sputtering to form these layers, ensuring reduced crystal defects and high crystallinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If oxide semiconductor films are used in transistors, then new semiconductor properties can be achieved, but impurity-induced carrier generation and crystal defects reduce reliability
Solution Approach 1:
The semiconductor device is divided into distinct functional layers: a first semiconductor film for the transistor channel, a second semiconductor film for parasitic capacitance control, and a third semiconductor film for impurity barrier functionality. This segmentation allows each layer to be optimized for its specific function while using the same oxide semiconductor material system.
Solution Approach 2:
The gate insulating film acts as an intermediary layer between the gate electrode and the active layer, preventing direct contact and reducing impurity-induced carrier generation. The second semiconductor film serves as an intermediary that controls parasitic capacitance between the source/drain regions and the substrate.
2Adaptability or versatility
If oxide semiconductor films are used, then semiconductor functionality is achieved, but parasitic capacitance affects transistor performance
Solution Approach 1:
The second semiconductor film functions as an intermediary layer positioned between the source/drain regions and the substrate, specifically designed to control parasitic capacitance. This layer mediates the electrical interaction between the active transistor components and the substrate, reducing unwanted capacitive effects.
Solution Approach 2:
The second semiconductor film is strategically positioned only in regions where parasitic capacitance control is needed, such as beneath the source and drain regions. This localized approach allows optimization of transistor performance without affecting other functional areas of the device.
3Ease of manufacture
If conventional manufacturing methods are used, then device fabrication is achieved, but crystal defects reduce device reliability
Solution Approach 1:
The manufacturing process utilizes specific parameter ranges for film formation, including temperature control during sputtering or CVD, oxygen partial pressure, and film thickness. These parameter optimizations ensure high crystallinity and low defect density in the oxide semiconductor films while maintaining manufacturing feasibility.
Solution Approach 2:
The device employs a composite structure with multiple oxide semiconductor films, each with potentially different compositions and properties. The first film may have one stoichiometry optimized for channel transport, while the second film has different properties optimized for capacitance control, creating a composite material system that achieves multiple goals 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
This configuration enhances the electrical properties of transistors, such as low off-current and stable threshold voltage, improving the reliability and performance of semiconductor devices in display applications.
Implementation Method 1
a gate insulating film sandwiched by the gate electrode and the active layer
Implementation Method 2
The active layer and the first semiconductor film are simultaneously formed and each contain an oxide semiconductor
Implementation Method 3
a manufacturing method that involves chemical vapor deposition and sputtering to form these layers
Data Source
AI summary
Disclosed is a semiconductor device including a gate wiring, an active layer, a gate insulating film, a first wiring, a second wring, and a first semiconductor film. The gate wiring includes a gate electrode. The active layer overlaps with the gate electrode and contains an oxide semiconductor. The gate insulating film is sandwiched by the gate electrode and the active layer. The first wiring and the second wiring are each located over the active layer and respectively include a first terminal and a second terminal which are electrically connected to the active layer. The first semiconductor film is located under and in contact with the first wiring and contains the oxide semiconductor.