Stacked Oxide Semiconductor Crystallization for Low Power Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor materials like SiC and GaN require high-temperature processing, making them unsuitable for thin film or three-dimensional devices, and existing metal oxide semiconductors tend to be n-type, leading to normally-on transistors with high power consumption and reliability issues.
Innovation Solution
A method for manufacturing stacked oxide materials using a sputtering method followed by crystallization heat treatment, where a first oxide crystal component grows from the surface inward, and a second oxide crystal component is stacked on top, with both components having common c-axes, allowing for homo- or hetero-crystal growth, and the oxide semiconductor is purified by removing impurities like water and hydrogen to achieve intrinsic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SiC or GaN is used as semiconductor material, then high-temperature crystallization is achieved, but the material cannot be used for thin film devices or three-dimensional devices
Solution Approach 1:
The patent changes the crystallization temperature parameter from conventional high temperatures (1500°C or higher for SiC/GaN) to a lower temperature range (400-800°C) by using oxide semiconductor materials. This parameter change enables the formation of crystalline semiconductor films at temperatures compatible with thin film and three-dimensional device fabrication processes, resolving the contradiction between achieving good crystallization and enabling thin film device application
Solution Approach 2:
The patent employs composite oxide semiconductor materials (such as In-Ga-Zn-O) that combine multiple metal elements to achieve both crystalline structure formation at low temperatures and desired semiconductor characteristics. This composite material approach allows the material to exhibit both insulating properties at room temperature and semiconducting properties when crystallized, enabling thin film device fabrication while maintaining reliable semiconductor performance
2Ease of manufacture
If existing metal oxide semiconductors are used, then transistors can be formed, but they tend to be n-type leading to normally-on transistors with high power consumption
Solution Approach 1:
The patent changes the electrical conductivity type parameter by precisely controlling the crystallization process and composition of oxide semiconductors. By achieving complete crystallization and controlling stoichiometry, the material transitions from n-type (normally-on) to intrinsic or p-type characteristics (normally-off), enabling low power consumption while maintaining ease of transistor fabrication
Solution Approach 2:
The patent applies different compositional ratios and crystallization conditions to different regions or layers of the oxide semiconductor film to achieve desired electrical characteristics. By optimizing local composition (e.g., In:Ga:Zn ratios) and crystallization parameters, the material achieves intrinsic or p-type conductivity for normally-off operation while maintaining manufacturability
3Reliability
If stacked oxide crystal components are formed with common c-axes, then homo- or hetero-crystal growth is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary action by forming a first oxide crystal component with a specific c-axis orientation before depositing the second oxide component. This preliminary crystallization creates a template that guides the subsequent hetero-crystal growth, ensuring common c-axes alignment and high transistor performance while simplifying the overall manufacturing process through sequential, controlled deposition steps
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
This approach results in transistors with high field-effect mobility, low off-current, and low power consumption, enabling the production of reliable semiconductor devices with improved manufacturing efficiency and cost-effectiveness.
Implementation Method 1
formed by stacking films by a sputtering method
Implementation Method 2
the films are subjected to crystallization heat treatment
Implementation Method 3
subjected to crystallization heat treatment
Data Source
AI summary
One embodiment is a method for manufacturing a stacked oxide material, including the steps of forming an oxide component over a base component; forming a first oxide crystal component which grows from a surface toward an inside of the oxide component by heat treatment, and leaving an amorphous component just above a surface of the base component; and stacking a second oxide crystal component over the first oxide crystal component. In particular, the first oxide crystal component and the second oxide crystal component have common c-axes. Same-axis (axial) growth in the case of homo-crystal growth or hetero-crystal growth is caused.