Oxide Semiconductor Layer Oxygen Vacancy Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Oxygen vacancies in oxide semiconductor layers of transistors increase during manufacturing, leading to poor electrical characteristics, such as normally-on behavior, increased leakage current, and shifted threshold voltage, due to insufficient oxygen supply and oxidation issues.
Innovation Solution
Incorporating an intermediate layer between the oxide semiconductor layer and the source/drain electrode layers, which are not in direct contact with the base insulating film, to prevent oxygen depletion and ensure efficient oxygen supply to the oxide semiconductor layer, using materials like aluminum oxide, gallium oxide, or yttrium oxynitride, and employing a three-layer oxide semiconductor structure with specific atomic ratios and crystal alignment to reduce oxygen vacancies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an oxide semiconductor layer is used as a channel formation region, then the transistor can be manufactured with simple processes, but oxygen vacancies increase during manufacturing leading to poor electrical characteristics
Solution Approach 1:
An intermediate layer made of oxide semiconductor material is introduced between the source/drain electrode layers and the base insulating film. This intermediate layer acts as a mediator that prevents direct contact between the electrode layers and base insulating film, thereby preventing oxygen depletion from the channel formation region while still allowing the transistor to be manufactured using simple processes.
Solution Approach 2:
The structure is segmented by dividing the original direct contact interface into separate components: the base insulating film, the intermediate layer, and the source/drain electrode layers. This segmentation allows the intermediate layer to specifically address the oxygen supply issue without requiring complete redesign of the manufacturing process.
2Device complexity
If the oxide semiconductor layer is in direct contact with the source/drain electrode layers, then the manufacturing process is simplified, but oxygen is depleted from the oxide semiconductor layer causing oxygen vacancies
Solution Approach 1:
The intermediate layer serves as a protective intermediary that prevents direct contact between the source/drain electrode layers and the base insulating film. This eliminates the oxygen depletion pathway while adding minimal structural complexity, as the intermediate layer can be formed using the same oxide semiconductor material and deposition processes.
Solution Approach 2:
The intermediate layer is strategically positioned only where oxygen depletion occurs (at the interface between source/drain electrode layers and base insulating film), while the channel formation region maintains its required properties. This localized intervention addresses the specific problem area without affecting other regions of the device.
3Ease of manufacture
If oxygen vacancies are present in the oxide semiconductor layer, then the manufacturing process remains simple, but the transistor exhibits normally-on behavior and increased leakage current
Solution Approach 1:
The intermediate layer acts as a protective barrier that prevents oxygen depletion during manufacturing, thereby preventing the formation of oxygen vacancies that would otherwise cause normally-on behavior and increased leakage current. This allows the transistor to achieve low leakage current characteristics without complicating the manufacturing process.
Solution Approach 2:
The intermediate layer is introduced in advance to prevent oxygen depletion before it can occur during subsequent manufacturing steps. By establishing this protective barrier beforehand, the patent prevents the formation of harmful oxygen vacancies and their associated negative effects on 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 solution effectively suppresses the increase in oxygen vacancies, stabilizes electrical characteristics, enhances field-effect mobility, and improves the reliability and power efficiency of the transistors by maintaining a low off-state current and stable threshold voltage.
Implementation Method 1
an intermediate layer which is not in direct contact with the base insulating film
Implementation Method 2
oxygen supply to the oxide semiconductor layer
Data Source
AI summary
A semiconductor device with a structure in which an increase in the number of oxygen vacancies in an oxide semiconductor layer can be suppressed and a method for manufacturing the semiconductor device are provided. The semiconductor device includes an oxide insulating layer; intermediate layers apart from each other over the oxide insulating layer; a source electrode layer and a drain electrode layer over the intermediate layers; an oxide semiconductor layer that is electrically connected to the source electrode layer and the drain electrode layer and is in contact with the oxide insulating layer; a gate insulating film over the source electrode layer, the drain electrode layer, and the oxide semiconductor layer; and a gate electrode layer that is over the gate insulating film and overlaps with the source electrode layer, the drain electrode layer, and the oxide semiconductor layer.