Indium Tin Zinc Oxide Semiconductor for Display Device Charge Mobility
Solution Overview
Problem
Current thin film transistor technologies face limitations in manufacturing high-performance displays due to low charge mobility in amorphous silicon and high costs, uniformity issues with polysilicon, and variability in oxide semiconductor characteristics, making it challenging to produce large-sized display panels with optimal performance and cost-effectiveness.
Innovation Solution
A display device utilizing an oxide semiconductor layer composed of indium, tin, and zinc, with specific atomic percentage ranges and ratios, which enhances charge mobility, etch rate, and threshold voltage, allowing for efficient manufacturing of thin film transistors with improved performance and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If amorphous silicon is used to form a semiconductor layer, then manufacturing cost is reduced, but charge mobility is low and high performance cannot be achieved
Solution Approach 1:
The patent changes the material composition parameters by using oxide semiconductor (In-Ga-Zn-O) instead of conventional amorphous silicon, achieving high charge mobility (1-100 cm²/Vs) while maintaining compatibility with existing thin film transistor manufacturing processes, thus resolving the contradiction between low cost and high performance
Solution Approach 2:
The patent employs a composite oxide semiconductor material comprising indium, gallium, and zinc in specific atomic ratios (In: 10-50 at%, Ga: 5-30 at%, Zn: 10-50 at%). This composite material combines the advantages of different elements to achieve both high charge mobility and manufacturing feasibility
2Reliability
If polysilicon is used to form a semiconductor layer, then charge mobility is high and high performance can be achieved, but manufacturing cost rises and uniformity is reduced
Solution Approach 1:
The patent changes the material type from polysilicon to oxide semiconductor, which can be deposited at lower temperatures and with better uniformity control, while maintaining high charge mobility through compositional optimization, thus reducing manufacturing cost and improving uniformity
Solution Approach 2:
The patent optimizes the local composition of the oxide semiconductor by controlling the atomic ratios of indium, gallium, and zinc within specific ranges, achieving high charge mobility in the channel region while maintaining overall manufacturing uniformity across large substrate areas
3Reliability
If oxide semiconductor is used to form a semiconductor layer, then charge mobility is higher and ON/OFF ratio is improved, but characteristics vary according to composition and etching characteristics are inconsistent
Solution Approach 1:
The patent establishes specific parameter ranges for the oxide semiconductor composition (In: 10-50 at%, Ga: 5-30 at%, Zn: 10-50 at%) that simultaneously optimize charge mobility, threshold voltage, and etching characteristics, ensuring consistent performance across mass production
Solution Approach 2:
The patent achieves homogeneous etching characteristics by optimizing the gallium and zinc content in the oxide semiconductor, which provides consistent reactivity with etchants across different regions of the substrate, eliminating variability in etching rates and improving manufacturing precision
Data Source
AI summary
A display device includes a first substrate, a gate line disposed on the first substrate and including a gate electrode, a gate insulating layer disposed on the gate line, a semiconductor layer disposed on the gate insulating layer, a data line disposed on the semiconductor layer and connected to a source electrode, a drain electrode disposed on the semiconductor layer and facing the source electrode and a passivation layer disposed on the data line, in which the semiconductor layer is formed of an oxide semiconductor including indium, tin, and zinc. The indium is present in an amount of about 5 atomic percent (at %) to about 50 at %, and a ratio of the zinc to the tin is about 1.38 to about 3.88.