Transistor Contact Structure With Carrier Injection Layers
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Solution Overview
Problem
Transistor structures face poor device performance and reliability issues due to process damage at the contact regions between the semiconductor channel and the source and drain electrodes, leading to low 'on' current and degraded performance.
Innovation Solution
Incorporation of one or more carrier injection layers at the interfaces between the semiconductor channel and the source and drain electrodes, engineered to facilitate charge carrier injection, with materials having a work function between the channel and electrode work functions to mitigate the high injection barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide semiconductor transistors are processed at low temperatures for BEOL integration, then previously fabricated FEOL devices are not damaged, but the injection barrier at contact regions remains high causing poor device performance
Solution Approach 1:
A carrier injection layer is introduced as an intermediary between the source/drain electrodes and the oxide semiconductor channel. This intermediate layer has a work function specifically engineered to be between the electrode work function and the channel work function, creating a gradual transition that reduces the injection barrier and facilitates carrier transport without requiring high-temperature processing.
Solution Approach 2:
The work function of the carrier injection layer is optimized as a key parameter to bridge the energy gap between the metal electrode and the oxide semiconductor channel. By selecting materials with appropriate work functions and adjusting layer composition, the injection barrier is reduced while maintaining compatibility with low-temperature BEOL processing conditions.
2Reliability
If carrier injection layers are added at the contact regions, then the injection barrier is reduced and carrier injection is enhanced, but the device structure becomes more complex
Solution Approach 1:
The contact structure is segmented into multiple functional layers: the metal electrode, the carrier injection layer with optimized work function, and the oxide semiconductor channel. This segmentation allows each layer to be independently optimized for its specific function while maintaining overall device performance and compatibility with existing fabrication processes.
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
Improves device performance by reducing the high injection barrier, enhancing carrier injection, and increasing the 'on' current and reliability of the transistor structures.
Implementation Method 1
engineered to facilitate charge carrier injection, with materials having a work function between the channel and electrode work functions to mitigate the high injection barrier
Data Source
AI summary
Transistor structures and methods thereof include one or more carrier injection layers at the interfaces between a semiconductor channel and source and drain electrodes. The one or more carrier injection layers may be engineered to facilitate the injection of charge carriers across the interfaces between the channel and the source and drain electrodes. The one or more carrier injection layers may include a material having a work function that is between the work function of the channel material and the work function of the source and drain electrodes to compensate for the injection barrier effect and provide improved device performance. Multiple carrier injection layers having different compositions may be utilized to provide for improved carrier injection while minimizing interface defect states.