Oxide TFT Channel Doping to Block Low-Resistance Edge Spread
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Solution Overview
Problem
To achieve higher resolution and density in oxide semiconductor thin-film transistors (TFTs) without reducing the resistance of the channel region, the source/drain regions need to be smaller and less resistive, while maintaining the designed resistance in the channel region, which is challenging due to the expansion of low-resistive regions into the channel area.
Innovation Solution
Implanting an element, such as oxygen ions, into specific regions of the oxide semiconductor to increase resistance, thereby preventing the expansion of low-resistive regions into the channel area by compensating for oxygen vacancies caused by source/drain electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If source/drain regions are made smaller and less resistive to achieve higher resolution and density, then the resolution and density are improved, but the resistance of the channel region is reduced due to expansion of low-resistive regions into the channel area
Solution Approach 1:
The patent applies local quality by creating a non-uniform concentration distribution of resistance-increasing elements within the oxide semiconductor layer. Specifically, the element concentration is higher in the channel region and lower in the source/drain regions, allowing each region to have its required electrical properties: high resistance in the channel for proper switching characteristics and low resistance in source/drain for efficient current flow, thus resolving the contradiction between achieving high density and maintaining channel resistance
Solution Approach 2:
The patent segments the oxide semiconductor layer into regions with different element concentrations. By controlling the implantation process to create distinct concentration zones (higher in channel, lower in source/drain), the patent effectively divides the uniform semiconductor layer into functionally differentiated segments, enabling simultaneous optimization of channel resistance and source/drain conductivity for high-resolution, high-density TFTs
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 method maintains the desired resistance characteristics of the channel region, allowing for higher density and resolution of TFTs by preventing the reduction in resistance at the channel ends, thus ensuring the TFTs function as intended.
Implementation Method 1
implanting an element capable of increasing resistance of an oxide semiconductor into a selected region of the oxide semiconductor layer
Data Source
AI summary
An oxide semiconductor thin-film transistor device includes a gate electrode region, an oxide semiconductor region, a first source/drain electrode region, and a second source/drain electrode region. The oxide semiconductor region has a concentration distribution of an element capable of increasing resistance of an oxide semiconductor. The concentration distribution shows a first concentration at the centroid of a channel region overlapping the gate electrode region in a planar view. The concentration distribution shows a concentration higher than the first concentration in a vicinity of at least a part of a boundary defining an outer end of the channel region.