Thin Film Transistor Ring Drain Electrode Current Stability
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Solution Overview
Problem
The stability of drain current in thin film transistors is affected by the occurrence of pinch-off regions in the channel, leading to fluctuations that impact the display effect of display devices.
Innovation Solution
A thin film transistor design featuring a drain electrode shaped like a ring and a source electrode shaped elliptically or circularly, with the drain electrode surrounding the source electrode, which results in a logarithmic change in the channel's length-to-width ratio, reducing current fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional linear source-drain electrode patterns are used, then the structure is simple and easy to manufacture, but the channel length-to-width ratio changes linearly causing large drain current fluctuations
Solution Approach 1:
The source and drain electrodes are designed with curved patterns (circular arcs or annular rings) instead of conventional linear patterns. The drain electrode forms an annular ring structure surrounding the source electrode, creating a curved channel geometry. This curvature transforms the linear relationship between channel dimensions and drain current into a logarithmic relationship, significantly reducing current fluctuations and improving device reliability.
2Productivity
If the channel length is reduced to increase transistor density, then the productivity increases, but the pinch-off effect becomes more pronounced causing greater current instability
Solution Approach 1:
By designing the drain electrode as an annular ring with inner radius R1 and outer radius R2, the channel forms a curved geometry between source and drain. The effective channel length becomes the radial distance (R2-R1) while the channel width corresponds to the angular extent. This curved configuration allows shorter channel lengths to achieve higher transistor density while the logarithmic current-characteristic relationship maintains stability even at reduced channel dimensions.
Solution Approach 2:
The invention transitions from a conventional one-dimensional linear channel to a two-dimensional annular channel geometry. The drain electrode forms a ring structure with radial and angular dimensions, allowing the channel to extend in multiple directions. This dimensional change enables compact packaging for higher density while the distributed current path through the annular geometry reduces the impact of pinch-off effects.
Data Source
AI summary
A thin film transistor includes a gate pattern, a gate insulating layer, an active layer and a source-drain pattern, which are all arranged on a substrate. The source-drain pattern includes a source electrode and a drain electrode. An orthographic projection of the drain electrode on the substrate is shaped like a ring, and an orthographic projection of the source electrode on the substrate is elliptic or circular. The drain electrode is arranged around the source electrode.