Oxide Semiconductor Transistor with Segmented Insulating Layers
Solution Overview
Problem
Transistors using oxide semiconductors face reliability issues due to fluctuations in threshold voltage after bias-temperature stress tests, leading to unstable electric characteristics and reduced reliability.
Innovation Solution
Incorporating an insulating layer that releases oxygen by heating in contact with the channel region and a layer releasing a smaller amount of oxygen in contact with the source and drain regions, to reduce interface state density and oxygen deficiency, thereby stabilizing the transistor's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating layer that releases oxygen by heating is used in contact with the channel region, then interface state density is reduced and threshold voltage stability is improved, but device complexity increases due to the need for different insulating layers in different regions
Solution Approach 1:
The patent applies local quality by using different insulating layers with different oxygen release characteristics in different regions of the semiconductor device. Specifically, a first insulating layer with high oxygen release is used in the channel region to reduce interface states and improve threshold voltage stability, while a second insulating layer with low oxygen release is used in the source and drain regions to prevent resistance increase. This localized differentiation resolves the contradiction by tailoring the insulating layer properties to the specific requirements of each region.
Solution Approach 2:
The patent segments the insulating layer structure into multiple distinct regions with different material compositions and oxygen release characteristics. The insulating layer is divided into a first insulating layer contacting the channel region and a second insulating layer contacting the source and drain regions. This segmentation allows each region to be optimized independently for its specific function, resolving the contradiction between improving reliability and managing device complexity.
2Reliability
If oxygen is released to the channel region to reduce interface states, then charge trapping is suppressed, but oxygen deficiency in source and drain regions may increase causing resistance increase
Solution Approach 1:
The patent implements local quality by assigning different oxygen release characteristics to different regions. The first insulating layer in the channel region is designed to release oxygen to reduce interface states and suppress charge trapping, while the second insulating layer in the source and drain regions is designed to release minimal oxygen to prevent resistance increase. This localized control of oxygen distribution resolves the contradiction between improving reliability and maintaining manufacturing precision.
Solution Approach 2:
The patent uses the insulating layers as intermediary materials that mediate the oxygen distribution throughout the device. The first insulating layer acts as an oxygen source for the channel region, while the second insulating layer acts as an oxygen barrier for the source and drain regions. This intermediary approach allows precise control over oxygen distribution, resolving the contradiction between suppressing charge trapping and preventing resistance increase.
3Device complexity
If a single insulating layer is used for both channel and source/drain regions, then device complexity is reduced, but threshold voltage fluctuation increases due to insufficient interface state control
Solution Approach 1:
The patent applies local quality by differentiating the insulating layer properties across different device regions. The first insulating layer with high oxygen release is specifically placed in the channel region to reduce interface states and stabilize threshold voltage, while the second insulating layer with low oxygen release is placed in the source and drain regions. This localized differentiation resolves the contradiction by providing the necessary interface state control without excessive complexity.
Solution Approach 2:
The patent segments the insulating layer into functionally distinct regions to achieve proper threshold voltage control. By dividing the insulating layer structure into a first layer for channel contact and a second layer for source/drain contact, the patent achieves the threshold voltage stability needed for reliable operation while keeping the overall structure manageable through clear functional segmentation.
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 approach effectively suppresses charge trapping and resistance increases in the source and drain regions, maintaining stable on-state current and reducing off-state current and threshold voltage fluctuations, enhancing the overall reliability of the semiconductor device.
Implementation Method 1
an insulating layer from which oxygen is released by heating is used as an insulating layer in contact with a channel region of an oxide semiconductor layer
Data Source
AI summary
An insulating layer which releases a large amount of oxygen is used as an insulating layer in contact with a channel region of an oxide semiconductor layer, and an insulating layer which releases a small amount of oxygen is used as an insulating layer in contact with a source region and a drain region of the oxide semiconductor layer. By releasing oxygen from the insulating layer which releases a large amount of oxygen, oxygen deficiency in the channel region and an interface state density between the insulating layer and the channel region can be reduced, so that a highly reliable semiconductor device having small variation in electrical characteristics can be manufactured. The source region and the drain region are provided in contact with the insulating layer which releases a small amount of oxygen, thereby suppressing the increase of the resistance of the source region and the drain region.