Dense Oxide Semiconductor Layer for Short-Channel Transistors
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Solution Overview
Problem
As semiconductor processes become finer, the shrinking size of transistors leads to a short channel effect, causing issues like threshold voltage variation, carrier velocity saturation, and degradation of subthreshold characteristics, necessitating a method to overcome these challenges and reduce off-current.
Innovation Solution
A semiconductor device with an oxide semiconductor layer, where the measurement density is 90% or more of the theoretical density, and the layer includes In, Ga, and Zn, with a specific composition ratio, is used, along with a gate insulating layer and a gate electrode, to improve film density and reduce short channel effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the transistor size is decreased to increase integration, then the area occupied by transistors is reduced, but short channel effects worsen causing threshold voltage variation and off-current increase
Solution Approach 1:
The patent changes the physical and chemical parameters of the semiconductor layer by forming an oxide semiconductor layer with high density (measurement density of 90% or more of theoretical density) and specific composition ratios (In:Ga:Zn = 1:1:1 to 3:1:1). This parameter change in material density and composition resolves the short channel effect while maintaining miniaturized transistor dimensions
Solution Approach 2:
The patent uses a composite oxide semiconductor material containing multiple elements (In, Ga, Zn, and optionally Sn, Hf, Al) with specific composition ratios. This composite material structure provides both the density required to suppress short channel effects and the electrical properties needed for reliable operation in miniaturized transistors
2Area of moving object
If the gate electrode and channel contact area is decreased to reduce transistor size, then the transistor area is reduced, but carrier velocity saturation occurs
Solution Approach 1:
The patent changes the material parameters of the oxide semiconductor layer to achieve high carrier mobility despite reduced gate-channel contact area. The specific composition ratios and high density of the oxide semiconductor material enable maintaining carrier velocity in miniaturized devices where the gate electrode contact area with the channel is reduced
3Reliability
If the oxide semiconductor layer density is increased to overcome short channel effects, then the film density is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise parameter ranges for the oxide semiconductor layer including measurement density of 90% or more of theoretical density, thickness of 1 nm to 10 nm, and specific composition ratios (In:Ga:Zn = 1:1:1 to 3:1:1). These controlled parameters achieve high film density to suppress short channel effects while providing clear manufacturing targets for process control
Solution Approach 2:
The patent applies different composition ratios and density requirements to different regions or layers of the oxide semiconductor structure. The ability to control local composition (In:Ga:Zn ratios) and local density (90% or more of theoretical density) allows optimization of electrical properties in the channel region while managing manufacturing precision through region-specific parameter control
Data Source
AI summary
Provided are a semiconductor device including an oxide semiconductor layer and an electronic device including the semiconductor device. The semiconductor device includes a substrate, a first electrode provided on the substrate, a second electrode provided on the first electrode, an oxide semiconductor layer provided between the first electrode and the second electrode, a gate electrode provided in a thickness direction of the oxide semiconductor layer, and a gate insulating layer provided between the oxide semiconductor layer and the gate electrode, wherein a measurement density relative to a theoretical density of the oxide semiconductor layer is about 90% or more. The oxide semiconductor layer of the semiconductor device may have a more uniform and improved film density, and may improve the reliability of the device due to the improved film density.