Oxide Semiconductor Composition for Low-Swing Transistors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current transistors using In--Ga--Zn-based oxide semiconductors face challenges with high subthreshold swing (S value) and threshold voltage, resulting in suboptimal electrical characteristics.
Innovation Solution
A sputtering target with a composite structure, including microcrystalline regions of insulating and conductive materials, is used to deposit oxide or oxynitride semiconductors, which are then integrated into a transistor structure with a gate insulating film, enhancing electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-layer stack of indium zinc oxide and IGZO is used as the active layer, then field-effect mobility is improved, but subthreshold swing increases and threshold voltage becomes negative
Solution Approach 1:
The patent changes the compositional parameters of the oxide semiconductor by introducing aluminum and controlling the In:Al:Zn atomic ratio (preferably 4:2:3 or 5:1:6). This parameter adjustment modifies the electrical characteristics to achieve appropriate threshold voltage and subthreshold swing while maintaining high field-effect mobility
Solution Approach 2:
The patent uses a composite oxide semiconductor structure containing multiple elements (In, Al, Zn) with specific atomic ratios. The composite nature of the material allows simultaneous optimization of multiple electrical characteristics including mobility, threshold voltage, and subthreshold swing
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 improved field-effect mobility and reliability of semiconductor devices by optimizing the semiconductor structure and composition, leading to better switching characteristics and reduced oxygen vacancies.
Implementation Method 1
A sputtering target with a composite structure, including microcrystalline regions of insulating and conductive materials, is used to deposit oxide or oxynitride semiconductors
Data Source
AI summary
A novel oxide semiconductor, a novel oxynitride semiconductor, a transistor including them, or a novel sputtering target is provided. A composite target includes a first region and a second region. The first region includes an insulating material and the second region includes a conductive material. The first region and the second region each include a microcrystal whose diameter is greater than or equal to 0.5 nm and less than or equal to 3 nm or a value in the neighborhood thereof. A semiconductor film is formed using the composite target.