Solid Precursor Feed System for HTS Tape Deposition

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Solution Overview

Problem

Current precursor delivery systems for high-temperature superconductor fabrication in vapor deposition reactors face challenges such as variable and unpredictable vapor delivery rates, precursor degradation, and low growth rates, which hinder the production of high-quality HTS wires with desired critical current capacities, especially in high magnetic fields.

Innovation Solution

A precursor feed system with a powder feeder assembly, load lock assembly, weighing mechanism, and control system that converts continuous mass data into a precise feed screw rate to deliver target precursor powder feed rates to the evaporator, ensuring stable and controlled delivery of solid precursors for high-temperature superconductor thin film deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solid precursor materials are used in vapor deposition, then precursor degradation is avoided, but vapor delivery rates become variable and unpredictable

Engineering Contradiction:

Improveprecursor stabilityVSAvoidvapor delivery rate control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The system changes the physical state parameter of the precursor from solid to vapor through controlled heating, enabling precise delivery rate control. The heating rate and temperature are carefully regulated to achieve consistent vapor generation from solid precursors, resolving the contradiction between maintaining precursor stability and controlling vapor delivery precision.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If flash evaporation approach is used, then precursor properties are preserved, but condensation leads to fouling and plugging

Engineering Contradiction:

Improveprecursor property preservationVSAvoidcondensation fouling

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system uses an inert atmosphere (nitrogen or argon) throughout the vaporization and delivery pathway to prevent condensation of precursor vapors. By maintaining positive pressure inert gas flow, the system eliminates the harmful condensation effect while preserving precursor properties during flash evaporation.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The system replaces the mechanical flash evaporation approach with a controlled thermal vaporization process using heated boats or susceptors. This substitution allows for gradual, controlled vapor generation rather than abrupt flash evaporation, reducing the tendency for condensation and fouling while maintaining precursor property preservation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If solvent-based aerosol MOCVD is used, then precursor delivery is improved, but large quantities of solvent vapor are generated

Engineering Contradiction:

Improveprecursor delivery controlVSAvoidsolvent vapor generation

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The system extracts and eliminates the solvent component from the precursor delivery system by using pure solid precursor materials. The precursors are vaporized directly without dissolution in organic solvents, thereby removing the source of harmful solvent vapors while maintaining precise precursor delivery control through controlled thermal vaporization.

Inventive Principle:

Principle #2Taking out (Extraction)

4Ease of manufacture

If volumetric feed screw type feeder is used, then solid precursor delivery is achieved, but self-segregation causes variable delivery rates

Engineering Contradiction:

Improvesolid precursor handlingVSAvoidpowder delivery rate control

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The system replaces the mechanical volumetric feed screw feeder with a thermal vaporization approach using heated boats or susceptors. Instead of mechanically conveying solid precursors through screw feeders that cause segregation, the system loads precursors into heated zones where they vaporize directly, eliminating the mechanical handling issues while achieving precise delivery control through temperature regulation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 system achieves precise and stable precursor delivery, enhancing the growth rate and critical current capacity of HTS wires, maintaining desired crystallographic structure and pinning center distribution, even in high magnetic fields, while reducing production costs and complexity.

Implementation Method 1

a weighing mechanism configured to provide continuous mass data of precursor powder in the powder vessel

Methodology Applied

Scientific EffectWeight measurement:

Implementation Method 2

an evaporator; wherein the control system converts the continuous mass data to a feed screw rate to deliver a target precursor powder feed rate to the evaporator

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS11781216B2Solid precursor feed system for thin film depositions

Publication Date: 2023.10.10 METOX INT INC

AI summary

A dry powder MOCVD vapor source system is disclosed that utilizes a gravimetric powder feeder, a feed rate measurement and feeder control system, an evaporator and a load lock system for continuous operation for thin film production, particularly of REBCO type high temperature superconductor (HTS) tapes.