Oxide Semiconductor Oxygen Defect Control via Plasma Treatment
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Solution Overview
Problem
Thin film semiconductor devices with oxide semiconductor layers suffer from oxygen defects caused by manufacturing processes, leading to unstable characteristics, negative shifts in threshold voltage, and luminance variations when used in display devices.
Innovation Solution
A thin film semiconductor device is manufactured with a plasma treatment process that controls the density of oxygen defects in the oxide semiconductor layer, ensuring the density of states (DOS) satisfies specific relationships, thereby reducing oxygen defects and stabilizing device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma treatment is performed on oxide semiconductor film to suppress oxygen defects, then oxygen defect density is reduced, but oxide semiconductor may be damaged and characteristics may be degraded
Solution Approach 1:
The patent applies parameter changes by precisely controlling plasma treatment conditions including power density (0.2-1.0 W/cm²), pressure (2.0-3.0 Torr), and treatment time (30-120 seconds). These parameter optimizations enable effective oxygen defect suppression while preventing oxide semiconductor damage, resolving the contradiction between reliability improvement and harm prevention.
Solution Approach 2:
The patent implements dynamics by adjusting plasma treatment parameters based on the specific oxide semiconductor material composition and film thickness. The treatment conditions are dynamically optimized for different materials (In-Ga-Zn-O, In-Al-Zn-O, etc.) to achieve maximum oxygen defect suppression with minimum damage.
2Reliability
If conventional plasma treatment conditions are used, then oxygen defects are suppressed, but threshold voltage shifts and luminance variations occur
Solution Approach 1:
The patent achieves precise threshold voltage control by optimizing plasma treatment parameters to maintain oxygen partial pressure of 3.0-7.0×10⁻³ Pa during treatment. This precise parameter control suppresses oxygen defects without causing threshold voltage shifts or luminance variations, simultaneously improving reliability and manufacturing precision.
Solution Approach 2:
The patent implements feedback control by monitoring and adjusting plasma treatment conditions based on measured oxygen defect density and threshold voltage characteristics. Treatment parameters are refined based on feedback from electrical measurements to achieve stable device characteristics.
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
The controlled plasma treatment significantly decreases the negative shift in threshold voltage and mobility curve peak, resulting in more stable characteristics and reduced luminance variations, enhancing the reliability of the thin film semiconductor devices for display applications.
Implementation Method 1
a plasma treatment is performed on an oxide semiconductor film to suppress occurrence of oxygen defects
Data Source
AI summary
A thin film semiconductor device comprises a substrate, a gate electrode disposed above the substrate, an oxide semiconductor layer disposed above the substrate so as to oppose the gate electrode, a channel protective layer disposed on the oxide semiconductor layer, and a source electrode and a drain electrode each connected to the oxide semiconductor layer. The density of states DOS [eV−1cm−3] of oxygen defects in the oxide semiconductor layer satisfies the following relationship:DOS≦1.710×1017×(Ec−E)2−6.468×1017×(Ec−E)+6.113×1017 provided that 2.0 eV≦Ec−E≦2.7 eVwhere Ec [eV] is an energy level of a conduction band edge of the oxide semiconductor layer and E [eV] is a predetermined energy level of the oxide semiconductor layer.