Oxide TFT Contact Structure for High-Density Display Switching
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Solution Overview
Problem
In display devices, transistors used in pixel and driver circuits require high on/off ratios and fast operation to manage increasing pixel density, with existing thin film transistors struggling to meet these demands, especially in high-density display applications.
Innovation Solution
A transistor structure incorporating an oxide conductive layer with a crystal region between the source and drain electrodes and an oxide semiconductor layer, along with an oxide insulating layer, is used to reduce contact resistance and enhance switching characteristics, allowing for high-speed operation and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a thin film transistor is used in high-density display devices, then the device can handle increasing pixel density, but the transistor operation speed becomes insufficient
Solution Approach 1:
The patent changes the physical and chemical parameters of the source and drain regions by forming oxide conductive layers with crystal regions. This structural parameter change reduces contact resistance and improves carrier transport, enabling faster transistor operation that keeps pace with high pixel density requirements
Solution Approach 2:
The patent uses composite material structures by combining oxide semiconductor layers with oxide conductive layers containing crystal regions. This composite approach creates optimal electrical characteristics at the interface between source/drain electrodes and the semiconductor channel, resolving the speed limitation in high-density displays
2Ease of manufacture
If conventional thin film transistor structures are used, then manufacturing is simpler, but contact resistance is high and switching characteristics are poor
Solution Approach 1:
The oxide conductive layer acts as an intermediary between the source/drain electrodes and the oxide semiconductor layer. This intermediate layer with crystal region structure mediates the electrical contact, reducing contact resistance and improving switching characteristics while maintaining compatibility with existing manufacturing processes
Data Source
AI summary
It is an object to manufacture a highly reliable display device using a thin film transistor having favorable electric characteristics and high reliability as a switching element. In a bottom gate thin film transistor including an amorphous oxide semiconductor, an oxide conductive layer having a crystal region is formed between an oxide semiconductor layer which has been dehydrated or dehydrogenated by heat treatment and each of a source electrode layer and a drain electrode layer which are formed using a metal material. Accordingly, contact resistance between the oxide semiconductor layer and each of the source electrode layer and the drain electrode layer can be reduced; thus, a thin film transistor having favorable electric characteristics and a highly reliable display device using the thin film transistor can be provided.