Hydrogen Barrier Thin-Film Transistor for BEOL Channel Protection
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Solution Overview
Problem
Thin film transistors (TFTs) in the back-end-of-line (BEOL) of semiconductor fabrication are susceptible to degradation by ambient gases like hydrogen, which can corrupt layers and degrade device effectiveness.
Innovation Solution
Incorporating a hydrogen diffusion barrier film layer to protect the semiconducting channel layer from ambient gases during the formation of BEOL devices, thereby preventing hydrogen penetration and maintaining the integrity of the TFTs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If BEOL transistors are exposed to ambient environment during fabrication, then device functionality can be added at BEOL, but hydrogen from ambient environment corrupts the transistor layers and degrades device effectiveness
Solution Approach 1:
A hydrogen diffusion barrier film is introduced as an intermediary layer between the oxide semiconductor layer and the ambient environment. This barrier film selectively blocks hydrogen diffusion while allowing the transistor to maintain its BEOL integration functionality, thus resolving the contradiction between adaptability and reliability.
Solution Approach 2:
The hydrogen diffusion barrier film creates a protected, inert environment for the oxide semiconductor layer by preventing hydrogen from the ambient environment from reaching and corrupting the transistor layers, thereby maintaining device effectiveness while allowing BEOL integration.
2Reliability
If hydrogen diffusion barrier film is added to protect channel region, then device reliability is improved, but fabrication process complexity increases
Solution Approach 1:
A thin film hydrogen diffusion barrier is applied to the oxide semiconductor layer. This thin film provides effective hydrogen protection while adding minimal structural complexity to the device, allowing reliability improvement without significantly increasing fabrication process complexity.
Solution Approach 2:
The transistor structure is enhanced by incorporating a hydrogen diffusion barrier film as an additional functional layer. This composite structure combines the oxide semiconductor layer with the barrier film to achieve both protection and functionality without requiring fundamentally new 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
The hydrogen diffusion barrier film effectively blocks hydrogen diffusion, allowing for precise control of source and drain region formation and protecting the channel region from damage during processing, enhancing the reliability and performance of TFTs.
Implementation Method 1
a patterned hydrogen diffusion barrier film disposed on the semiconductor layer, wherein the hydrogen diffusion barrier film blocks hydrogen penetration into a channel region of the semiconductor layer during a thermal annealing process
Implementation Method 2
during a thermal annealing process wherein hydrogen is doped into other portions of the semiconductor layer to form active source and drain regions
Data Source
AI summary
A thin film transistor and method of making the same, the thin film transistor including: a substrate; a word line disposed on the substrate; a semiconductor layer disposed on the substrate, the semiconductor layer having a source region, a drain region, and a channel region disposed between the source and drain regions and overlapping with the word line in a vertical direction perpendicular to a plane of the substrate; a hydrogen diffusion barrier layer overlapping with the channel region in the vertical direction; a gate dielectric layer disposed between the channel region and the word line; and source and drain electrodes respectively electrically coupled to the source and drain regions.