Fluorine-Graded Gate Insulator for LCD Leakage Current
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Solution Overview
Problem
Conventional liquid crystal display (LCD) devices face issues with impurities diffusing into the channel area of switching elements, leading to increased leakage current during the manufacturing process of switching elements.
Innovation Solution
The LCD device incorporates a gate electrode, semiconductor layer, drain electrode, source electrode, and a fluorine-doped gate insulating layer with a specific concentration gradient, along with ohmic contact layers having high impurity concentrations, to prevent impurities from entering the channel area. The manufacturing method involves forming these layers and patterning them using photoresist patterns and hydrophobization processes to ensure impurity exclusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional switching element manufacturing process is used, then the manufacturing process is simple, but impurities diffuse into the channel area causing increased leakage current
Solution Approach 1:
The gate insulating layer is divided into multiple sub-layers with different fluorine concentrations. The first sub-layer has a higher fluorine concentration than the second sub-layer, creating a gradient structure that prevents impurity diffusion into the channel area while maintaining manufacturing feasibility
Solution Approach 2:
Different regions of the gate insulating layer are assigned different fluorine concentrations based on their functional requirements. The region adjacent to the channel area has higher fluorine concentration to prevent impurity diffusion, while other regions have lower concentrations to maintain overall device performance
2Reliability
If impurity concentration in ohmic contact layer is increased, then contact resistance is reduced, but impurity diffusion into channel area increases
Solution Approach 1:
The gate insulating layer with graded fluorine concentration acts as an intermediary barrier between the high impurity concentration ohmic contact layer and the channel area. This intermediate structure allows the ohmic contact layer to maintain high impurity concentration for low contact resistance while preventing impurity diffusion into the channel area through the fluorine-rich gate insulating layer
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 prevents impurities from entering the channel area, reducing leakage current and enhancing the reliability and performance of the LCD device.
Implementation Method 1
a gate insulating layer between the gate electrode and the semiconductor layer, the gate insulating layer comprising fluorine A concentration of the fluorine is decreasing, as the fluorine of the gate insulating layer being more adjacent to the substrate
Implementation Method 2
an ohmic contact layer between the semiconductor layer and the drain electrode and between the semiconductor layer and the source electrode The ohmic contact layer may have an impurity concentration of about 2*1021 atom/cm3 or higher
Implementation Method 3
removing a portion of the first photoresist pattern and the second photoresist pattern to form a third photoresist pattern which is disposed to correspond to a channel area of the semiconductor layer; hydrophobizating the third photoresist pattern; forming an impurity semiconductor material above the gate insulating layer and the semiconductor layer using the third photoresist pattern that is hydrophobizated as a mask
Data Source
AI summary
A liquid crystal display (LCD) device capable of perventing impurities from permeating into a channel area of a switching element, the LCD device including: a gate electrode above a substrate; a semiconductor layer which overlaps the gate electrode; a drain electrode and a source electrode which overlap the semiconductor layer; an ohmic contact layer between the semiconductor layer and the drain electrode and between the semiconductor layer and the source electrode; a pixel electrode which is connected to one of the drain electrode and the source electrode; and a gate insulating layer between the gate electrode and the semiconductor layer, the gate insulating layer comprising fluorine. A concentration of the fluorine is decreasing, as the fluorine of the gate insulating layer being more adjacent to the substrate.