Oxide Semiconductor Microvoids for Hydrogen Trapping
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Solution Overview
Problem
Oxide semiconductor transistors face challenges with hydrogen incorporation, leading to shifts in threshold voltage and instability in electric characteristics due to hydrogen's role as a donor, making it difficult to control and minimize hydrogen levels effectively.
Innovation Solution
The formation of microvoids in the source and drain regions of the oxide semiconductor film using ion implantation or doping with specific ion concentrations captures hydrogen, thereby stabilizing the electric characteristics of the transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrogen is present in the oxide semiconductor film, then electrical conductivity is increased, but threshold voltage shifts in the negative direction and electric characteristics become unstable
Solution Approach 1:
The patent introduces microvoids (porous structures) in the source and drain regions of the oxide semiconductor film. These microvoids act as hydrogen trapping sites, capturing hydrogen atoms that would otherwise cause threshold voltage shifts. The porous structure allows selective hydrogen capture in specific regions while maintaining the overall semiconductor functionality.
Solution Approach 2:
The patent applies different hydrogen concentrations to different regions of the oxide semiconductor film. The source and drain regions contain microvoids with captured hydrogen, while the channel region maintains low hydrogen concentration for stable threshold voltage. This local differentiation resolves the contradiction by allowing hydrogen benefits in contact regions while preventing harmful effects in the channel.
2Reliability
If hydrogen concentration is reduced in the oxide semiconductor film, then threshold voltage stability is improved, but electrical conductivity decreases
Solution Approach 1:
The patent creates spatial variation in hydrogen distribution across the oxide semiconductor film. Source and drain regions have higher hydrogen concentration (captured in microvoids) to maintain conductivity, while the channel region has lower hydrogen concentration for threshold voltage stability. This local quality differentiation allows simultaneous achievement of both conductivity and threshold voltage control.
Solution Approach 2:
The microvoids act as intermediary structures that capture and localize hydrogen atoms. Instead of uniformly distributing hydrogen throughout the film (which would compromise threshold voltage), the microvoids serve as intermediate storage sites in the source and drain regions, allowing hydrogen to be present where it benefits conductivity without affecting the channel region's threshold voltage stability.
3Reliability
If ion implantation is used to form microvoids, then hydrogen capture capability is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent utilizes ion implantation parameters (ion type, concentration, energy) to create microvoids with specific hydrogen capture characteristics. By adjusting these parameters, the microvoids can be optimized for maximum hydrogen capture efficiency. This parameter-based approach allows control over hydrogen capture capability without fundamentally changing the manufacturing process architecture.
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 captures hydrogen in the channel region, reducing its concentration and improving the reliability and stability of the semiconductor device by minimizing the impact of hydrogen on threshold voltage shifts.
Implementation Method 1
hydrogen is diffused into the oxide semiconductor film from an insulating film which is in contact with the oxide semiconductor film
Implementation Method 2
a microvoid is provided in a source region and a drain region formed in an oxide semiconductor film, so that hydrogen included in a channel region in an oxide semiconductor film can be captured
Data Source
AI summary
A highly reliable semiconductor device is manufactured by giving stable electric characteristics to a transistor in which an oxide semiconductor film is used. In a transistor using an oxide semiconductor film for an active layer, a microvoid is provided in a source region and a drain region adjacent to a channel region. By providing a microvoid in the source region and the drain region formed in an oxide semiconductor film, hydrogen contained in the channel region of an oxide semiconductor film can be captured in the microvoid.