Oxide Semiconductor Wiring Stack With Vanadium Oxygen Barrier
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Solution Overview
Problem
Oxygen extraction from oxide semiconductor transistors during high-temperature processes adversely affects transistor operation due to the formation of oxygen vacancies at the interface with metal wires, leading to deterioration in device properties.
Innovation Solution
Incorporation of a vanadium oxide layer as an oxygen barrier film between the oxide semiconductor and metal wiring layer to prevent oxygen extraction, combined with a nitride layer to prevent diffusion of metal into the oxide layer, thereby maintaining transistor integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If metal wiring layer is placed directly on oxide semiconductor layer, then device structure is simplified, but oxygen extraction occurs at elevated temperatures causing transistor performance deterioration
Solution Approach 1:
An oxygen barrier layer comprising vanadium oxide is introduced between the metal wiring layer and the oxide semiconductor layer. This intermediary layer prevents oxygen extraction from the oxide semiconductor by the metal wiring during elevated temperature processes, thereby maintaining transistor performance while allowing direct contact structure for simplified fabrication.
2Reliability
If oxygen barrier layer is added between oxide semiconductor and metal wiring, then oxygen extraction is prevented improving transistor reliability, but device structure becomes more complex
Solution Approach 1:
The oxygen barrier layer is selectively formed only in regions where oxygen extraction is problematic, specifically between the metal wiring layer and the oxide semiconductor layer. This localized approach provides the necessary protection while minimizing the overall structural complexity and maintaining fabrication efficiency.
3Reliability
If vanadium oxide layer is used as oxygen barrier, then oxygen extraction is reduced maintaining low electrical resistance, but additional manufacturing steps are required
Solution Approach 1:
The vanadium oxide layer is formed by controlling the oxidation state of vanadium during the deposition process. By adjusting the oxygen partial pressure and deposition conditions, the layer achieves the optimal oxidation state that provides effective oxygen barrier properties while maintaining low electrical resistance, thus preserving transistor performance.
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 vanadium oxide layer effectively reduces oxygen extraction, preventing oxygen vacancies and maintaining low electrical resistance, thus preserving transistor performance and reliability.
Implementation Method 1
oxygen will be extracted from the oxide semiconductor in a reduction reaction with surrounding or adjacent metal wires at elevated temperatures
Data Source
AI summary
According to one embodiment, a semiconductor device includes an oxide semiconductor layer, an oxide conductor layer disposed on the oxide semiconductor layer, a first oxide layer disposed on the oxide conductor layer and comprising vanadium oxide, and a metal wiring layer disposed on the first oxide layer.