Nanostructure Electrical Devices with Shadow Mask Growth
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Solution Overview
Problem
Current methods for fabricating hybrid semiconductor-superconductor nanostructures require post-growth processing, which can damage the semiconductor and introduce device-to-device variations, especially for superconductors like niobium-based alloys and tantalum, limiting their exploration and scalability in nanoscale electronic devices.
Innovation Solution
A method involving specially designed growth substrates with patterned dielectric materials and shadow structures allows for in-situ growth and deposition of nanoscale devices, eliminating the need for post-processing by controlling the growth and deposition of materials within a vacuum environment, enabling scalable production of high-quality nanoscale electrical devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If post-growth processing is used to remove superconductor material, then device architecture can be incorporated, but the semiconductor is damaged and device performance degrades
Solution Approach 1:
The patent applies preliminary action by designing the growth substrate with pre-formed shadow structures (raised platforms) before nanostructure growth. These shadow structures are positioned to automatically define the device architecture during the growth process itself, eliminating the need for subsequent processing steps that would damage the semiconductor. The shadow structures cast shadows during deposition that precisely define where superconductor material should be removed to create Josephson junctions and other device features.
Solution Approach 2:
The growth substrate with integrated shadow structures serves itself by automatically defining the device architecture during nanostructure growth. The shadow structures self-organize the deposition process to create the desired device pattern without requiring external intervention or post-growth processing. The semiconductor nanostructures grow in a self-aligned manner relative to the shadow structures, ensuring precise positioning and eliminating damage from subsequent processing.
2Ease of manufacture
If post-growth processing is used to remove superconductor material, then device architecture can be incorporated, but device-to-device variations are introduced
Solution Approach 1:
The growth substrate is prepared in advance with precisely positioned shadow structures that define the device architecture. This preliminary configuration ensures that all devices on the substrate follow the same geometric template during growth, eliminating variations introduced by subsequent processing steps. The shadow structures are fabricated with high precision before growth, ensuring uniform device dimensions and performance across the entire substrate.
Solution Approach 2:
The growth substrate is segmented into multiple identical shadow structure units, each serving as a template for device fabrication. This segmentation allows parallel fabrication of multiple devices with identical geometries, ensuring uniformity across device-to-device variations. Each shadow structure unit is independently positioned and configured, enabling scalable production while maintaining precision.
3Reliability
If serial work is used where device is designed around each nanowire, then individual device quality can be optimized, but scalability is limited
Solution Approach 1:
The growth substrate with shadow structures serves multiple functions simultaneously: it defines device architecture, positions nanostructures, controls material deposition, and enables parallel fabrication of multiple devices. This universal platform allows the same substrate design to be used for fabricating large numbers of identical devices, achieving both high quality and scalability. The shadow structures are universally applicable templates that can define various device geometries.
Solution Approach 2:
The substrate is divided into multiple identical shadow structure units that can simultaneously produce multiple devices in parallel. This segmentation transforms the process from serial (one device at a time) to parallel (many devices simultaneously), achieving scalability while maintaining consistent device quality through identical template designs. Each segment functions independently but follows the same design rules.
4Ease of manufacture
If post-growth processing is used, then superconductor material can be selectively removed, but the delicate superconducting properties are degraded
Solution Approach 1:
The shadow structures are pre-positioned on the growth substrate before superconductor deposition. During the deposition process, these shadow structures automatically define where superconductor material should be absent by casting shadows that prevent deposition in those regions. This preliminary configuration eliminates the need for subsequent removal processing, preserving the delicate superconducting properties of the deposited material while achieving selective positioning.
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 ensures the preservation of the delicate superconducting properties and reduces device variations, enabling the scalable fabrication of high-quality nanoscale devices with precise control over material deposition and growth, enhancing the integration of superconducting materials like niobium-based alloys and tantalum.
Implementation Method 1
the platform can be arranged to form a shadow mask on the nanostructure
Implementation Method 2
epitaxial and atomically perfect interface between a semiconductor and a superconductor, which can be provided by growing the semiconductor and superconductor in a single grown-run
Data Source
AI summary
The present disclosure further relates to nanostructures, in particular hybrid nanostructures with patterned growth of various layers for use in nanoscale electronic devices, such as hybrid semiconductor nanostructures with patterned growth and/or deposition of superconducting material for use in quantum devices. The presently disclosed method can be utilized for in-situ manufacturing of nanoscale electronic devices that have not been contaminated by ex-situ processes. One embodiment relates to a method for manufacturing a substrate for growth of crystalline nanostructures, the method comprising the steps of: depositing one or more layers of a crystal growth compatible dielectric material, such as silicon oxide, in a predefined pattern on the surface of a crystal growth compatible substrate to create a predefined etch pattern of said crystal growth compatible material, and selectively etching the substrate surface around said etch pattern to provide at least one under-etched platform which is vertically raised from the etched substrate surface.