Oxide Semiconductor Gate Stack With Al Oxide Oxygen Barrier
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Solution Overview
Problem
The challenge is to create a semiconductor device with an oxide semiconductor channel that maintains high mobility and reliability while minimizing defects in the insulating layer, which affects oxygen supply and leads to variations in device characteristics.
Innovation Solution
A semiconductor device configuration with a metal oxide layer containing aluminum, positioned between the gate insulating layer and the oxide semiconductor layer, where the metal oxide layer's thickness is between 1 nm and 4 nm, acts as a gas barrier to regulate oxygen and hydrogen, ensuring sufficient oxygen supply to the oxide semiconductor layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If an insulating layer with high oxygen content is formed to supply oxygen to the oxide semiconductor layer, then oxygen supply is improved, but the insulating layer contains more defects causing electron-trapping and characteristic variation
Solution Approach 1:
A metal oxide layer (containing Al, In, Ga, or Zn) is introduced as an intermediary layer between the insulating layer and the oxide semiconductor layer. This intermediary layer has high oxygen release capability and acts as a mediator to supply oxygen to the oxide semiconductor layer without requiring the insulating layer to have high oxygen content, thereby avoiding the defect formation problem in the insulating layer.
2Quantity of substance
If the metal oxide layer thickness is increased to improve oxygen supply, then oxygen supply capability is improved, but the layer contains more defects causing electron-trapping
Solution Approach 1:
The thickness of the metal oxide layer is optimized to a specific range (1 nm to 4 nm) to achieve the best balance between oxygen supply capability and defect reduction. This parameter optimization ensures sufficient oxygen supply to the oxide semiconductor layer while minimizing the formation of defects that cause electron-trapping and characteristic variation.
3Reliability
If an insulating layer with fewer defects is used to reduce electron-trapping, then characteristic variation is reduced, but oxygen supply to the oxide semiconductor layer is insufficient
Solution Approach 1:
The oxygen supply function is segmented from the insulating layer and assigned to a dedicated metal oxide layer. The insulating layer can be optimized for low defect density while the metal oxide layer is optimized for high oxygen release capability, achieving both characteristic stability and sufficient oxygen supply.
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 enhances the semiconductor device's mobility and reliability by reducing defects and oxygen vacancies, resulting in stable electrical characteristics and improved reliability test results.
Implementation Method 1
the metal oxide layer's thickness is between 1 nm and 4 nm, acts as a gas barrier to regulate oxygen and hydrogen
Data Source
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AI summary
A semiconductor device according to an embodiment includes: a substrate; a metal oxide layer arranged above the substrate and having aluminum as the main component of the metal oxide layer; an oxide semiconductor layer arranged above the metal oxide layer; a gate electrode facing the oxide semiconductor layer; and a gate insulating layer between the oxide semiconductor layer and the gate electrode, wherein a thickness of the metal oxide layer is 1 nm or more and 4 nm or less. A thickness of the metal oxide layer is 1 nm or more and 3 nm or less.