Oxide Semiconductor Transistor Structure With Hydrogen Barrier Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor devices using oxide semiconductors face challenges in achieving stable electrical characteristics, low leakage current in the off state, and normally-off electrical characteristics, which are crucial for reliable transistor performance.
Innovation Solution
A method for manufacturing semiconductor devices involves forming specific layers and structures, including a first conductor, insulators, and an oxide semiconductor, with careful control of hydrogen permeability and the use of materials like tantalum and aluminum oxides to create a reliable transistor with stable electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional transistors are used without specific hydrogen barrier structures, then manufacturing is simpler, but electrical characteristics become unstable and leakage current increases
Solution Approach 1:
The transistor structure is divided into multiple functional layers including a base insulator, a hydrogen barrier insulator layer, and a cap insulator. This segmentation allows each layer to perform its specific function - the hydrogen barrier insulator prevents hydrogen diffusion to the oxide semiconductor, while other layers provide insulation and structural support, thereby improving electrical stability without excessive complexity
Solution Approach 2:
A hydrogen barrier insulator layer is introduced as an intermediary between the oxide semiconductor and the underlying structures. This intermediate layer specifically blocks hydrogen diffusion, preventing hydrogen from reaching the oxide semiconductor and causing electrical instability, thus resolving the contradiction between reliability and structural simplicity
2Reliability
If hydrogen barrier structures are added to prevent hydrogen diffusion, then leakage current is reduced, but manufacturing complexity increases
Solution Approach 1:
The hydrogen barrier insulator layer is designed with specific material composition and thickness parameters optimized to achieve effective hydrogen blocking. By carefully controlling these parameters, the layer provides sufficient barrier functionality while minimizing the number of additional manufacturing steps required, thus balancing leakage current control with manufacturing ease
3Reliability
If multiple insulator layers with different hydrogen permeability are used, then transistor reliability improves, but device complexity increases
Solution Approach 1:
Different insulator layers are positioned at specific locations where hydrogen diffusion paths exist. The hydrogen barrier insulator is placed directly adjacent to the oxide semiconductor where hydrogen blocking is most critical, while other insulator layers are positioned where general insulation is needed. This localized quality assignment improves transistor reliability by targeting hydrogen diffusion prevention at critical interfaces without adding unnecessary layers throughout the entire structure
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 approach results in semiconductor devices with stable electrical characteristics, low leakage current, and normally-off characteristics, enhancing the reliability and performance of transistors.
Implementation Method 1
forming a second insulator that is less permeable to hydrogen than the first insulator, over the first insulator
Implementation Method 2
the second conductor is less permeable to hydrogen than the third conductor
Data Source
AI summary
First to third insulators are successively formed in this order over a first conductor over a semiconductor substrate; a hard mask with a first opening is formed thereover; a resist mask with a second opening is formed thereover; a third opening is formed in the third insulator; a fourth opening is formed in the second insulator; the resist mask is removed; a fifth opening is formed in the first to third insulators; a second conductor is formed to cover an inner wall and a bottom surface of the fifth opening; a third conductor is formed thereover; polishing treatment is performed so that the hard mask is removed, and that levels of top surfaces of the second and third conductors and the third insulator are substantially equal to each other; and an oxide semiconductor is formed thereover. The second insulator is less permeable to hydrogen than the first and third insulators, the second conductor is less permeable to hydrogen than the third conductor.