Oxide Semiconductor Transistor Oxygen Zoning for Stable Threshold Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Oxide semiconductor transistors face challenges in reducing contact resistance and maintaining threshold voltage stability, particularly due to oxygen concentration variations in the channel layer, which can lead to increased contact resistance and shifted threshold voltage during subsequent processing steps.
Innovation Solution
The design includes a substrate with first and second compound layers and a channel layer, where the oxygen concentration is selectively reduced in specific regions through a metal-oxygen reaction, using a metal layer with high oxygen reactivity, such as Al, Zn, Ni, Sn, Mg, or Fe, to form compound layers that reduce contact resistance and maintain stable threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a separate process is used to solve threshold voltage shift, then threshold voltage stability is improved, but contact resistance increases
Solution Approach 1:
The patent applies local quality by creating distinct oxygen concentration zones within the channel layer. The first region (near source/drain electrodes) maintains higher oxygen concentration to reduce contact resistance, while the second region (under gate electrode) has lower oxygen concentration to stabilize threshold voltage. This spatial differentiation of oxygen concentration allows simultaneous optimization of both contact resistance and threshold voltage stability without requiring separate corrective processes.
Solution Approach 2:
The channel layer is segmented into multiple regions with different oxygen concentrations. By dividing the channel layer into a first region contacting source/drain electrodes and a second region under the gate electrode, the patent enables independent optimization of electrical contact properties and threshold voltage characteristics in each segment, resolving the contradiction between contact resistance and threshold voltage stability.
2Stability of the object's composition
If oxygen concentration is reduced in the channel layer, then threshold voltage stability is improved, but contact resistance increases
Solution Approach 1:
The patent implements local quality by preventing uniform oxygen reduction across the entire channel layer. Instead, it maintains higher oxygen concentration in the first region (source/drain contact areas) to ensure low contact resistance, while selectively reducing oxygen concentration only in the second region (under gate electrode) to stabilize threshold voltage. This localized approach resolves the contradiction by applying different oxygen concentration levels to different functional regions.
Solution Approach 2:
The patent segments the channel layer into functionally distinct regions with different oxygen concentrations. The first region maintains higher oxygen for good electrical contact, while the second region has reduced oxygen for threshold voltage stability. This segmentation allows the system to achieve both low contact resistance and stable threshold voltage simultaneously, overcoming the limitation of uniform oxygen reduction.
3Productivity
If channel length is reduced for high integration, then device integration is improved, but off-current increases
Solution Approach 1:
The patent applies local quality by creating specific oxygen concentration profiles in different regions of the channel layer. The first region near source/drain electrodes maintains higher oxygen concentration to form ohmic contacts and reduce off-current, while the second region under the gate has lower oxygen concentration to enable effective gate control. This localized oxygen engineering allows short channel transistors to maintain low off-current despite reduced channel length, enabling high integration without sacrificing reliability.
Solution Approach 2:
The patent utilizes parameter changes by precisely controlling oxygen concentration as a key parameter in different channel layer regions. By adjusting oxygen concentration locally - higher in contact regions and lower in the gate-controlled region - the patent optimizes both electrical contact properties and transistor switching characteristics, enabling high integration with reduced channel length while maintaining low off-current through parameter optimization.
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 reduces contact resistance between electrodes and the channel layer, maintaining low contact resistance and stable threshold voltage, enhancing the performance and integration of oxide semiconductor transistors in memory devices.
Implementation Method 1
reducing the oxygen concentration in the second and third regions of the channel layer to be less than that in the first region of the channel layer through a metal-oxygen reaction
Implementation Method 2
portions of the channel layer contacting the first and second compound layers may not include oxygen in its entire thickness
Data Source
AI summary
The present disclosure relates to oxide semiconductor transistors, methods of manufacturing the same, and/or memory devices including the oxide semiconductor transistors. The oxide semiconductor transistor includes first and second compound layers provided on a substrate, a channel layer in contact with the first and second compound layers, a first electrode facing a portion of the channel layer, a second electrode facing the first compound layer with the channel layer therebetween, and a third electrode facing the second compound layer with the channel layer therebetween. An oxygen concentration of a region of the channel layer facing the first electrode is greater than that of the remaining regions of the channel layer. A buffer layer may further be provided between the channel layer and the second and third electrodes. The first and second compound layers may include oxygen and a metal.