Oxide Semiconductor ALD Process for Low-Variation Transistors
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Solution Overview
Problem
Existing semiconductor devices face challenges with variations in transistor electrical characteristics, reliability, electrical performance, miniaturization, integration, and power consumption, particularly in the use of oxide semiconductors.
Innovation Solution
A method involving the deposition of metal oxides using an Atomic Layer Deposition (ALD) process, including specific precursors and oxidizing gases, with controlled temperature and gas introduction steps to reduce hydrogen concentration and enhance thickness uniformity, is employed to form semiconductor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If oxide semiconductors are used in transistors, then power consumption is reduced, but variation in electrical characteristics increases
Solution Approach 1:
The patent changes the chemical composition parameters of the oxide semiconductor by introducing nitrogen and controlling oxygen content. This modifies the material properties to reduce carrier concentration and improve electrical characteristic uniformity while maintaining low power consumption characteristics
Solution Approach 2:
The patent creates a composite oxide semiconductor material containing nitrogen within the oxide structure. This composite approach combines the low power consumption advantage of oxide semiconductors with improved electrical characteristic uniformity through nitrogen incorporation
2Productivity
If transistor size is reduced for miniaturization, then integration density increases, but electrical characteristics become more variable
Solution Approach 1:
The patent modifies the oxide semiconductor composition by adding nitrogen and controlling oxygen content to reduce carrier concentration. This parameter change improves the uniformity of electrical characteristics, enabling better performance in miniaturized transistors with higher integration density
3Ease of manufacture
If conventional deposition methods are used, then manufacturing process is simple, but thickness uniformity and hydrogen control are poor
Solution Approach 1:
The patent employs Atomic Layer Deposition (ALD) which uses periodic alternation of precursor and oxidizing gas introduction. This periodic action enables precise control of film thickness and composition, achieving superior thickness uniformity compared to conventional continuous deposition methods
Solution Approach 2:
The patent changes the deposition parameters by using ALD with controlled temperature (210-300°C) and specific gas sequences. This enables precise control of film properties including thickness uniformity and hydrogen concentration reduction
4Ease of manufacture
If hydrogen is present in insulators, then deposition process is easier, but hydrogen transfers to metal oxide causing electrical characteristic degradation
Solution Approach 1:
The patent converts the harmful effect of hydrogen by providing dedicated hydrogen absorption sites in the insulator structure. The insulator is designed to capture and retain hydrogen that would otherwise transfer to the metal oxide, thereby protecting electrical characteristics while simplifying deposition processes
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 method results in semiconductor devices with reduced transistor variation, improved reliability, enhanced electrical characteristics, higher on-state current, and lower power consumption, enabling miniaturization and integration.
Implementation Method 1
The metal oxide is deposited by an ALD method
Implementation Method 2
performing heat treatment, so that hydrogen in the first insulator, the second insulator, and the oxide is transferred and absorbed into the metal oxide
Data Source
AI summary
A semiconductor device in which variation in electrical characteristics is small is provided. A first insulator is deposited, a metal oxide is device over the first insulator, a second insulator is device over the metal oxide, an oxide film is device over the second insulator, and heat treatment is performed, whereby hydrogen in the first insulator, the second insulator, and the oxide is transferred and absorbed into the metal oxide. The metal oxide is formed by an ALD method.