Oxide Semiconductor Transistor Sidewall Insulator Design
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Solution Overview
Problem
Miniaturization of transistors leads to defects such as poor connection and short channel effects due to reduced coverage and increased electric field impact, which degrade electrical characteristics and increase power consumption.
Innovation Solution
A semiconductor device with an oxide semiconductor layer, source and drain electrodes having a multi-layer structure with a region extended in the channel length direction, and a sidewall insulating layer with a smaller length than the extended region, providing improved coverage and reducing the electric field impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If transistor size is reduced for miniaturization, then device size decreases and manufacturing efficiency increases, but connection reliability deteriorates due to reduced coverage and short channel effects occur due to increased electric field impact
Solution Approach 1:
The source electrode and drain electrode are segmented into multiple layers (first conductive layer and second conductive layer). The second conductive layer extends beyond the first conductive layer in the channel length direction, creating a segmented structure that improves coverage over the oxide semiconductor layer while maintaining miniaturization. This segmentation allows each layer to serve specific functions: the first layer provides primary conduction while the extended second layer ensures reliable electrical connection and reduces short channel effects.
Solution Approach 2:
The electrode structure transitions from a single-layer planar configuration to a multi-layer three-dimensional structure. The second conductive layer extends in the channel length direction beyond the first conductive layer, adding vertical and lateral dimensionality. This dimensional change increases the effective coverage area without proportionally increasing the footprint, thereby improving connection reliability while maintaining miniaturization.
2Volume of moving object
If transistor size is reduced for miniaturization, then device size decreases, but electrical characteristics deteriorate due to short channel effects
Solution Approach 1:
The second conductive layer is selectively extended in the channel length direction beyond the first conductive layer, creating a local quality variation in the electrode structure. This localized extension provides enhanced coverage and electric field management precisely where needed (at the edges in the channel length direction) to suppress short channel effects, while the rest of the transistor maintains its miniaturized dimensions.
3Volume of moving object
If transistor size is reduced for miniaturization, then device size decreases and manufacturing efficiency increases, but power consumption increases due to short channel effects
Solution Approach 1:
The multi-layer electrode structure segments the electrical conduction path, with the extended second conductive layer providing better coverage over the oxide semiconductor channel. This segmentation reduces short channel effects by improving electric field distribution, thereby reducing leakage current and power consumption while maintaining the miniaturized transistor size.
Data Source
AI summary
One object is to provide a semiconductor device that includes an oxide semiconductor and is reduced in size with favorable characteristics maintained. The semiconductor device includes an oxide semiconductor layer, a source electrode and a drain electrode in contact with the oxide semiconductor layer, a gate electrode overlapping with the oxide semiconductor layer; and a gate insulating layer between the oxide semiconductor layer and the gate electrode. The source electrode or the drain electrode includes a first conductive layer and a second conductive layer having a region extended in a channel length direction from an end face of the first conductive layer. The sidewall insulating layer has a length of a bottom surface in the channel length direction smaller than a length in the channel length direction of the extended region of the second conductive layer and is provided over the extended region.