Thin-Film Transistor Gate Protrusion for Short-Channel Stability
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Solution Overview
Problem
Thin film transistors with short channels face challenges in maintaining stable threshold voltage and driving stability due to conductorization penetration depth issues.
Innovation Solution
Incorporating a protrusion portion and an active hole in the thin film transistor design, which includes a channel area partially overlapping the gate electrode, a source area, and a drain area, helps control conductorization penetration depth and prevent threshold voltage shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the channel width is increased to improve current driving ability, then the mobility and current driving ability are improved, but the penetration depth of conductorization increases and the effective channel length decreases, deteriorating driving stability
Solution Approach 1:
The gate electrode is segmented into a main body portion and a protrusion portion that extends toward the source electrode. This segmentation allows the gate to exert control at multiple locations (over the channel and near the source), effectively increasing the controlled channel length without proportionally increasing the gate width, thus maintaining driving stability while improving current driving ability
Solution Approach 2:
The gate electrode structure is extended into a new spatial dimension by adding the protrusion portion that reaches toward the source electrode. This dimensional extension provides additional control over the channel region without simply increasing the channel width, thereby maintaining effective channel length control while enhancing current driving capability
2Area of stationary object
If the channel length is decreased to reduce device area, then the device area is reduced, but the threshold voltage shifts in the negative direction and driving stability deteriorates
Solution Approach 1:
The gate electrode is divided into a main body portion and a protrusion portion, with the protrusion extending toward the source electrode to provide additional control over the channel region. This segmentation enables effective threshold voltage control in short-channel devices by creating multiple control points, preventing negative threshold voltage shifts while maintaining reduced device area
Solution Approach 2:
The protrusion portion of the gate electrode provides localized control quality enhancement at the source-channel interface region. This local quality improvement针对性地 addresses the threshold voltage instability in short-channel devices without requiring overall channel length increase, thus maintaining small device area while ensuring threshold voltage stability
Data Source
AI summary
A thin film transistor includes an active layer; and a gate electrode spaced apart from the active layer and partially overlapping the active layer. The active layer includes a channel area partially overlapping the gate electrode; a source area connected to one side of the channel area; and a drain area connected to the other side of the channel area. The active layer defines an active hole in which the active layer absent, at least a part of the active hole overlaps the gate electrode in a plan view, and at least another part of the active hole extends beyond an edge of the gate electrode. The gate electrode includes a body portion and a protrusion portion protruding in a first direction, the first direction being a direction parallel to the shortest line connecting the source area and the drain area.