Multi-Gate Thin Film Transistors Light Blocking

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Thin film transistors in displays are prone to deterioration due to light irradiation, particularly when the active layer is exposed, leading to increased OFF state leakage current and degraded characteristics.

Innovation Solution

The design incorporates a top gate and bottom gate structure with a top gate side portion that surrounds the active layer, blocking light from both sides, and the use of non-transparent conductive materials for the gate, source, and drain to prevent light exposure, along with a gate insulating layer and passivation layer with specific via holes to enhance light blocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional thin film transistor structure with gate below active layer is used, then the structure is simple and easy to manufacture, but light irradiated from above the active layer cannot be blocked, causing increased OFF state leakage current and deterioration of transistor characteristics

Engineering Contradiction:

Improvetransistor characteristicsVSAvoidgate structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The gate is segmented into two separate gates: a bottom gate formed below the active layer and a top gate formed above the active layer. This segmentation allows each gate to independently block light from its respective direction, effectively preventing light-induced deterioration while maintaining manufacturing feasibility through sequential formation processes

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The gate structure transitions from a single-plane configuration to a three-dimensional arrangement with gates positioned both below and above the active layer. This dimensional expansion enables comprehensive light blocking from all directions, solving the limitation of conventional single-sided gate structures

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If the top gate side portion extends further to surround more of the active layer sidewall, then light blocking effectiveness improves, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvelight irradiation to active layerVSAvoidvia hole alignment

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The top gate side portion extends partially along the sidewall of the active layer rather than requiring complete 360-degree coverage. This partial extension provides sufficient light blocking effectiveness while reducing the stringency of alignment precision requirements, making the structure more manufacturable

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The top gate side portion is strategically positioned to cover critical regions where light would most effectively reach the active layer, such as areas above the channel region. This localized coverage approach optimizes light blocking effectiveness while minimizing the total extent of the structure and associated manufacturing complexity

Inventive Principle:

Principle #3Local quality

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 configuration effectively reduces light irradiation to the active layer, thereby preventing deterioration and improving the characteristics of the thin film transistor.

Implementation Method 1

the gate, the source and the drain are made of a non-transparent conductive material

Methodology Applied

Scientific EffectLight blocking: Absorption (EM radiation)

Data Source

PatentUS10340389B2Multi-gate thin film transistors, manufacturing methods thereof, array substrates, and display devices

Publication Date: 2019.07.02 BOE TECHNOLOGY GROUP CO LTD

AI summary

The present disclosure discloses in embodiments a thin film transistor and a manufacturing method thereof, an array substrate. The thin film transistor comprises: a base substrate, an active layer, a source, a gate, and a drain. Two ends of the active layer are connected to the source and the drain, respectively. The gate comprises a top gate and a bottom gate arranged opposite to each other in a direction perpendicular to the base substrate, the top gate comprising a top gate top portion and a top gate side portion connected to the top gate top portion, the top gate side portion extending from the top gate top portion towards the base substrate. The active layer is sandwiched between the top gate top portion and the bottom gate. A sidewall of the active layer is at least partially surrounded by the top gate side portion.