Semiconductor Substrate With Floating Electrode Leakage Prevention
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Solution Overview
Problem
Existing semiconductor device substrates with two gates face challenges in miniaturization and maintaining high-definition display capabilities due to increased leakage current and reduced ON current, as described in Japanese Patent No. 4275671.
Innovation Solution
A substrate design featuring a semiconductor layer with source, drain, and channel regions, along with a single continuous gate electrode that overlaps the channel and intermediate regions, and a floating electrode made of the same material as the source and drain electrodes, ensuring higher contact resistance and preventing leakage current without ON current drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two gates are used to prevent leakage current, then leakage current is reduced, but transistor size increases and ON current drops
Solution Approach 1:
The channel region is divided into multiple segments by introducing intermediate regions with different impurity concentrations between the source and drain. This segmentation allows the creation of multiple channel regions that work together to prevent leakage current while maintaining a single gate structure, thus reducing device complexity compared to using two gates.
Solution Approach 2:
Different regions within the semiconductor layer are given different local qualities through varying impurity concentrations. The intermediate regions have higher impurity concentrations than the channel regions, creating localized differences in electrical properties that prevent leakage current without requiring additional gates.
2Reliability
If two gates are used to prevent leakage current, then leakage current is reduced, but transistor area increases
Solution Approach 1:
The channel is segmented into multiple regions through intermediate zones with different impurity concentrations. This segmentation achieves leakage prevention through electrical field management within a compact area, avoiding the need for two separate gates that would increase transistor area.
3Reliability
If two gates are used to prevent leakage current, then leakage current is reduced, but ON current decreases
Solution Approach 1:
The intermediate regions are designed with specific impurity concentrations higher than the channel regions but lower than the source and drain regions. This local quality differentiation creates potential barriers that prevent leakage current while maintaining low resistance paths for ON current flow through the channel regions.
Solution Approach 2:
The impurity concentration parameter is varied across different regions to achieve the desired electrical characteristics. By carefully controlling the impurity concentration gradient from source/drain regions through intermediate regions to channel regions, the patent optimizes both leakage prevention and ON current maintenance.
Data Source
AI summary
A substrate for a semiconductor device includes: a base substrate; a semiconductor layer that has a source region, a drain region, a plurality of channel regions, and at least one intermediate region; a source electrode being in contact with the source region; a drain electrode being in contact with the drain region; a gate electrode that overlaps the plurality of channel regions, the intermediate region, and each of a part of the source electrode and a part of the drain electrode; and a floating electrode being in contact with the intermediate region. The size of an area where the floating electrode and the gate electrode overlap each other is smaller than the sum of the size of an area where the source electrode and the gate electrode overlap each other and the size of an area where the drain electrode and the gate electrode overlap each other.