Oxide Semiconductor Transistor Stack for Oxygen-Controlled Scaling
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving miniaturization, high integration, favorable electrical characteristics, small variation in transistor electrical characteristics, and low power consumption while maintaining reliability.
Innovation Solution
A semiconductor device with a transistor structure that includes an oxide semiconductor, multiple conductors, and insulators with specific thickness and permeability properties, where the oxide contains indium, zinc, and other metals, and the insulators are designed to control oxygen diffusion and hydrogen inhibition, enabling efficient oxygen supply to the channel formation region and preventing conductor oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the transistor size is reduced for miniaturization, then the device density increases, but the electrical characteristics variation increases and reliability deteriorates
Solution Approach 1:
The patent applies local quality by creating a non-uniform insulator structure where the insulator thickness varies across different regions. Specifically, the insulator is thinner in the channel formation region to allow oxygen diffusion for maintaining semiconductor properties, while being thicker in other regions to provide oxidation protection. This localized variation in insulator thickness enables miniaturization while maintaining electrical characteristic stability.
Solution Approach 2:
The patent changes the physical parameters of the insulator layer, specifically its thickness and oxygen permeability characteristics. By controlling the insulator thickness to be in a specific range (1 nm to 10 nm in the channel region) and selecting materials with appropriate oxygen diffusion properties, the patent achieves both miniaturization and reliable electrical characteristics through parameter optimization.
2Reliability
If multiple insulator layers are added to control oxygen diffusion, then the oxidation protection improves, but the device complexity increases
Solution Approach 1:
The patent segments the insulator function into multiple layers with different thicknesses and oxygen permeability characteristics. The first insulator layer provides oxygen diffusion to the channel region, while the second insulator layer provides oxidation protection to the conductor. This segmentation allows each layer to perform its specific function efficiently, improving oxidation protection while managing complexity through functional division.
Solution Approach 2:
The insulator layers serve multiple functions simultaneously: they act as gate dielectrics, oxygen diffusion barriers, and oxidation protection layers. By designing the insulator structure to fulfill multiple roles, the patent reduces the need for separate dedicated layers for each function, thereby improving oxidation protection without proportionally increasing device complexity.
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 enables the creation of semiconductor devices with high on-state current, low power consumption, and small variations in electrical characteristics, supporting miniaturization and high integration while ensuring reliability and improved frequency characteristics.
Implementation Method 1
the insulator is in contact with a top surface of the oxide and a sidewall of the opening included in the first insulator... enabling efficient oxygen supply to the channel formation region
Implementation Method 2
The fourth insulator is less permeable to oxygen than the third insulator is... preventing conductor oxidation
Implementation Method 3
a transistor using an oxide semiconductor has an extremely low leakage current in a non-conduction state... providing a semiconductor device with a high on-state current
Data Source
AI summary
A semiconductor device that can be miniaturized or highly integrated is provided. The semiconductor device includes a transistor. The transistor includes an oxide, a first conductor and a second conductor that are over the oxide, a first insulator over the first conductor and the second conductor, a second insulator in an opening included in the first insulator, a third insulator over the second insulator, a fourth insulator over the third insulator, and a third conductor over the fourth insulator. The opening includes a region overlapping with the oxide. The third conductor includes a region overlapping with the oxide with the second insulator, the third insulator, and the fourth insulator therebetween. The second insulator is in contact with a top surface of the oxide and a sidewall of the opening. The thickness of the second insulator is smaller than that of the third insulator. The fourth insulator is less permeable to oxygen than the third insulator is. The third conductor has a width greater than or equal to 3 nm and less than or equal to 15 nm in a cross-sectional view of the transistor in the channel length direction.