Inverted T-Shaped MBE Chamber Under Vector Magnetic Field
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Solution Overview
Problem
Current molecular beam epitaxy systems face challenges in growing high-quality spin semiconductor materials with uniform magnetic domain structures and efficient spin current polarization due to limitations in magnetic field control, interface quality, and surface contamination during characterization.
Innovation Solution
A molecular beam epitaxy system under a vector strong magnetic field with an inverted T-shaped ultrahigh vacuum growth and characterization chamber, equipped with a liquid-helium-free spiral magnet, dual-layer cooling, and in-situ characterization apparatus, allowing for precise control of magnetic fields and atomic-scale growth, and enabling in-situ characterization to avoid surface contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple components are equipped in the chamber to achieve fine growth of magnetic thin film material and in-situ characterization, then the growth quality and characterization precision are improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple evaporation sources, ion sources, and in-situ characterization apparatus into a single integrated molecular beam epitaxy chamber. This merging approach allows all components to share the same ultrahigh vacuum environment and strong magnetic field, achieving fine growth quality and in-situ characterization capability while avoiding the need for separate systems.
Solution Approach 2:
The chamber is designed as a multi-functional system that simultaneously performs molecular beam epitaxy growth, in-situ transport characterization, and spin electron transport measurement. The strong magnetic field chamber serves multiple purposes: providing magnetic field for spin control, maintaining ultrahigh vacuum for clean growth, and enabling in-situ measurements without sample exposure to air.
2Force
If the strong magnet chamber size is kept small (inner diameter smaller than 10 cm), then the magnetic field strength is improved, but the space for accommodating multiple components is reduced
Solution Approach 1:
The patent employs a vertical chamber configuration where evaporation sources and ion sources are positioned above the substrate, utilizing the vertical dimension rather than horizontal space. This allows multiple components to be accommodated in a compact horizontal footprint while maintaining strong magnetic field strength, as the chamber height can be extended without increasing the magnetic field chamber's horizontal dimensions.
3Measurement precision
If the sample is exposed to air for spin detection, then the detection capability is improved, but the surface contamination increases and spin characteristics are influenced
Solution Approach 1:
The patent implements in-situ transport characterization that allows spin detection to be performed within the ultrahigh vacuum chamber without breaking vacuum or exposing the sample to air. The chamber maintains vacuum conditions throughout the growth and characterization process, preventing surface contamination while enabling spin electron transport measurement through the chamber wall using external probes.
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 system achieves high-quality spin semiconductor growth with extended spin relaxation time and polarization, enabling precise control and characterization of spin electron transport, overcoming previous limitations in magnetic field control and surface contamination.
Implementation Method 1
molecular beam epitaxy under vector strong magnetic field
Implementation Method 2
improving larmor procession of spin electrons
Implementation Method 3
the magnetic moment of the material is basically parallel to the plane of the thin film
Implementation Method 4
molecular beam epitaxy under vector strong magnetic field
Implementation Method 5
molecular beam epitaxial growth of the thin film material can be realized
Implementation Method 6
the free path of molecules would be increased significantly (an average free path of the molecules can reach tens of meters under the vacuum of 10−4 Pa)
Implementation Method 7
the free path of molecules would be increased significantly
Implementation Method 8
the in-situ transport characterization of the sample is performed in an ultrahigh vacuum environment with strong magnetic field
Implementation Method 9
the spin detection is generally carried out outside the sample preparation chamber
Data Source
AI summary
The present invention discloses a molecular beam epitaxy under vector strong magnetic field and an in-situ characterization apparatus thereof. The apparatus mainly consists of an inverted T-shaped ultrahigh vacuum growth and characterization chamber with a compact structure and a strong magnet. The inverted T-shaped vacuum chamber portion, which disposed in the room-temperature chamber of the strong magnet, includes a compact epitaxial growth sample stage, a device capable of rotating angle between the growth and magnetic field directions, and an in-situ characterization apparatus. The portion disposed below the strong magnet includes a molecular beam source component such as evaporation source, plasma source etc., and a vacuum-pumping system. The present invention surmounts effectively the technical problems between the small volume of the strong magnetic field chamber and numerous components of the growth and test system, and realizes the molecular beam epitaxial growth and in-situ characterization under the strong magnetic field.