Oxide Semiconductor Gate Insulation for Hydrogen Trap Regions
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Solution Overview
Problem
Semiconductor devices using oxide semiconductors face challenges in preventing hydrogen from entering the channel region, which affects the threshold voltage stability and manufacturing yield due to hydrogen diffusion from insulating layers, and the use of excess oxygen in these layers reduces device reliability by acting as an electron trap.
Innovation Solution
Incorporating hydrogen trap regions in the oxide and gate insulating layers, formed by ion implantation of impurities, to prevent hydrogen from entering the channel region while ensuring sufficient hydrogen supply to the source and drain regions, thereby maintaining device reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If hydrogen trap regions are formed in insulating layers to prevent hydrogen entry into channel region, then threshold voltage stability is improved, but device complexity increases due to additional ion implantation processes
Solution Approach 1:
The insulating layers are segmented into functional regions: hydrogen trap regions (first and second regions) and non-trap regions (third and fourth regions). This segmentation allows selective hydrogen trapping in specific areas while maintaining other insulating functions in different areas, resolving the contradiction by localizing the complexity to where it is most needed.
Solution Approach 2:
Different regions of the insulating layers are given different properties: the first and second regions contain impurities to trap hydrogen, while the third and fourth regions maintain standard insulating properties. This local differentiation achieves threshold voltage stability without uniformly increasing device complexity throughout the entire structure.
2Object-affected harmful factors
If excess oxygen is added to insulating layers to trap hydrogen, then hydrogen entry into channel region is prevented, but device reliability deteriorates due to electron trapping
Solution Approach 1:
Excess oxygen (impurity) is localized only in the first and second regions where hydrogen trapping is needed, while the third and fourth regions maintain standard composition without excess oxygen. This prevents electron trapping in critical regions while still achieving hydrogen entry prevention where required.
Solution Approach 2:
The insulating layers are divided into segments with different compositions: impurity-containing regions for hydrogen trapping and impurity-free regions for maintaining reliability. This segmentation resolves the contradiction by separating the hydrogen trapping function from regions where electron trapping would be harmful.
3Manufacturing precision
If ion implantation is used to form hydrogen trap regions, then manufacturing precision is improved by controlling impurity concentration, but manufacturing complexity increases due to additional process steps
Solution Approach 1:
Ion implantation is performed at predetermined stages during the layer formation process to pre-establish hydrogen trap regions before final device assembly. This preliminary action allows precise control of impurity concentration in specific regions without requiring complex post-processing steps, resolving the contradiction between precision and complexity.
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 solution effectively suppresses hydrogen entry into the channel region, reducing variations in threshold voltage and improving manufacturing yield while maintaining device reliability by trapping hydrogen in specific regions of the insulating layers.
Implementation Method 1
Each of the source region, the drain region, and the second region contains an impurity. A hydrogen concentration of the second region is greater than a hydrogen concentration of the first region.
Implementation Method 2
Incorporating hydrogen trap regions in the oxide and gate insulating layers, formed by ion implantation of impurities
Data Source
AI summary
A semiconductor device according to an embodiment of the present invention includes an oxide insulating layer, an oxide semiconductor layer, a gate insulating layer, a gate electrode, and a protective insulating layer. The gate insulating layer includes a first region overlapping the gate electrode and a second region not overlapping the gate electrode. The second region is in contact with the protective insulating layer. The oxide insulating layer includes a third region overlapping the gate electrode and a fourth region not overlapping the gate electrode and the oxide semiconductor layer. The fourth region is in contact with the gate insulating layer. The oxide semiconductor layer includes a channel region, a source region, and a drain region. Each of the source region, the drain region, and the second region contains an impurity. A hydrogen concentration of the second region is greater than a hydrogen concentration of the first region.