Oxide Semiconductor Transistor with Segmented Gate and Oxygen-Rich Insulator
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Solution Overview
Problem
The integration and miniaturization of transistors with oxide semiconductors pose challenges in achieving good electrical characteristics, low off-state current, high on-state current, reliability, reduced power consumption, and high design flexibility, while existing techniques struggle with impurity diffusion and oxygen vacancies affecting transistor performance.
Innovation Solution
A semiconductor device structure incorporating multiple insulators and conductors with specific layering and etching methods to create a surrounded channel structure, using metal oxides as the semiconductor material, with excess oxygen in the insulators to reduce oxygen vacancies and impurity diffusion, and a manufacturing method involving dry etching with specific gas mixtures to form precise openings and layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If transistors are miniaturized and highly integrated, then device size and weight are reduced, but electrical characteristics deteriorate due to impurity diffusion and oxygen vacancies
Solution Approach 1:
The gate electrode is divided into two separate gates (first gate and second gate) positioned at opposite sides of the channel formation region. This segmentation allows independent control and optimization of electrical characteristics for each gate, enabling better performance in miniaturized devices by compensating for impurity diffusion and oxygen vacancy effects through dual-gate engineering
Solution Approach 2:
An insulator layer containing excess oxygen is introduced as an intermediary between the oxide semiconductor layer and the environment. This insulator acts as an oxygen reservoir that supplies oxygen to compensate for oxygen vacancies in the oxide semiconductor, thereby maintaining electrical characteristics during miniaturization without requiring larger device dimensions
2Adaptability or versatility
If oxide semiconductor transistors are used, then new material properties are achieved, but oxygen vacancies and impurity diffusion affect transistor performance
Solution Approach 1:
An insulator layer containing excess oxygen is formed beforehand in contact with the oxide semiconductor layer. This insulator serves as a preventive measure that cushions against oxygen vacancies by supplying oxygen during device operation, thereby protecting transistor performance before degradation occurs despite the inherent instability of oxide semiconductors
Solution Approach 2:
The chemical composition of the insulator is specifically designed to contain excess oxygen (non-stoichiometric composition). This parameter change in the insulator's oxygen content allows it to act as an oxygen source, dynamically compensating for oxygen loss in the oxide semiconductor and maintaining stable transistor performance
3Productivity
If process rule is decreased for miniaturization, then device integration increases, but manufacturing precision requirements increase
Solution Approach 1:
The first gate and second gate are formed using the same conductive material and similar fabrication processes, and the insulator layers are formed using consistent deposition methods. This merging of manufacturing approaches simplifies the overall fabrication process, maintaining manufacturing precision while enabling miniaturization and high integration through standardized process flows
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 miniaturized, highly integrated semiconductor devices with improved electrical characteristics, reduced power consumption, and enhanced reliability by minimizing oxygen vacancies and impurity diffusion, thereby achieving high on-state current and low off-state current.
Implementation Method 1
the insulator is provided along an inner wall of an opening provided in the third insulator, facing side surfaces of the first conductor and the second conductor, and a top surface of the oxide; the insulator contains excess oxygen to reduce oxygen vacancies
Implementation Method 2
a manufacturing method involving dry etching with specific gas mixtures to form precise openings and layers
Data Source
AI summary
A semiconductor device capable of miniaturization or high integration and manufacture of a semiconductor device are provided. The semiconductor device includes a first insulator; an oxide over the first insulator; a second insulator and first and second conductors over the oxide; a third conductor over the second insulator; a fourth conductor over the first conductor; a fifth conductor over the second conductor; a third insulator over the first insulator and the first and second conductors; a fourth insulator over the second and third insulators and the third conductor; and a fifth insulator over the fourth insulator. The first and second conductors are provided to face each other with the second insulator therebetween. The second insulator is provided along an inner wall of an opening provided in the third insulator, facing side surfaces of the first and second conductors, and a top surface of the oxide. The level of a top surface of the third conductor is higher than the levels of top surfaces of the second and third insulators. The fourth insulator is provided along the top surfaces of the second and third insulators and the top surface and a side surface of the third conductor.