Oxide Semiconductor Gate Insulator Structure for Stable Miniaturization
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Solution Overview
Problem
Current semiconductor devices face challenges in miniaturization, high integration, achieving favorable electrical characteristics, reducing variation in transistor electrical characteristics, ensuring reliability, attaining high on-state current, and low power consumption.
Innovation Solution
A semiconductor device is designed with a metal oxide channel formation region, specific conductor and insulator layers, and a unique insulating structure that includes a first insulator with a barrier property against oxygen and hydrogen, and a second insulator with a lower barrier property, to optimize electrical performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transistor size is reduced for miniaturization and high integration, then device density increases, but electrical characteristics variation and reliability deteriorate
Solution Approach 1:
The patent applies local quality by creating a multi-layer insulating structure with different barrier properties at different locations. The first insulator layer provides high barrier properties against oxygen and hydrogen diffusion near the metal oxide semiconductor interface, while the second insulator layer provides lower barrier properties. This localized differentiation of insulating properties allows the device to maintain electrical stability despite miniaturization, as the critical interface region receives enhanced protection while other regions have adequate insulation.
Solution Approach 2:
The patent employs composite materials by combining multiple insulator layers with different compositions and barrier properties. The first insulator (e.g., aluminum oxide or hafnium oxide) and second insulator (e.g., silicon oxide) form a composite insulating structure that leverages the high barrier properties of the first material at the critical interface and the adequate insulation properties of the second material, achieving both miniaturization and reliability.
2Loss of energy
If oxide semiconductor is used for low leakage current, then power consumption decreases, but oxygen diffusion and hydrogen contamination affect electrical characteristics
Solution Approach 1:
The patent converts the harmful effect of oxygen diffusion and hydrogen contamination into a benefit by using the first insulator layer as an oxygen barrier that prevents oxygen from diffusing into the metal oxide semiconductor channel. This barrier layer, positioned at the critical interface, transforms the potential harm of oxygen diffusion (which would degrade the low-leakage-current property) into a protective feature that maintains the oxide semiconductor's excellent electrical characteristics.
Solution Approach 2:
The first insulator layer acts as an intermediary between the metal oxide semiconductor and the external environment, blocking oxygen and hydrogen diffusion while allowing the oxide semiconductor to maintain its low leakage current properties. This intermediate barrier layer mediates the interaction between the semiconductor and contaminating elements, protecting the semiconductor's electrical characteristics.
3Speed
If gate insulator thickness is reduced for miniaturization, then transistor switching speed increases, but electrical characteristics variation increases
Solution Approach 1:
The patent applies local quality by providing enhanced barrier properties specifically at the gate insulator interface with the metal oxide semiconductor through the first insulator layer. This localized enhancement ensures uniform electrical characteristics across the device while maintaining thin overall gate insulator thickness for fast switching, as the critical interface region receives specialized protection against oxygen and hydrogen diffusion.
Solution Approach 2:
The gate insulator structure uses composite materials with the first insulator (high barrier property) and second insulator (adequate insulation property) forming a multi-layer composite. This composite structure maintains thin total thickness for fast switching while the first layer's high barrier properties ensure uniform electrical characteristics by preventing contamination at the critical interface.
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 semiconductor device achieves miniaturization, high integration, reduced variation in transistor characteristics, improved electrical performance, enhanced reliability, high on-state current, and low power consumption.
Implementation Method 1
The first insulator is a material through which oxygen is less likely to pass than the second insulator
Implementation Method 2
The first insulator is a material through which oxygen is less likely to pass than the second insulator
Data Source
AI summary
A semiconductor device that can be miniaturized or highly integrated and a manufacturing method thereof are provided. A semiconductor device includes a metal oxide, a first conductor and a second conductor over the metal oxide, a first insulator positioned over the metal oxide and between the first conductor and the second conductor, a second insulator over the first insulator, a third insulator over the second insulator, a third conductor over the third insulator, a fourth insulator positioned between the first conductor and the first insulator, and a fifth insulator positioned between the second conductor and the first insulator. The first insulator is in contact with the top surface and the side surface of the metal oxide, and oxygen is less likely to pass through the first insulator than the second insulator. The first conductor, the second conductor, the fourth insulator, and the fifth insulator contain the same metal element. In a cross-sectional view in a channel length direction, a distance from the first conductor to the first insulator is greater than or equal to a thickness of the first insulator and less than or equal to a distance from the third conductor to the metal oxide.