CVD Reactor with Reflector for Homogeneous Boron Deposition

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Solution Overview

Problem

Existing chemical vapor deposition methods for producing elemental boron and advanced ceramic powders face issues with impurity formation, non-homogeneous temperature distribution, and the difficulty in separating boron from substrates due to the formation of intermediate compounds, leading to reduced purity and efficiency.

Innovation Solution

A reactor design featuring a quartz inner tube surrounded by a heating element and a reflective outer tube, which provides homogenous temperature distribution and minimizes radiative energy losses, allowing for the deposition of boron and ceramic powders on the inner surface of the quartz tube, avoiding the formation of intermediate compounds and enabling efficient separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If metallic substrates (titanium, zirconium, tungsten, tantalum, molybdenum, nickel, graphite) are used for boron deposition, then boron can be deposited on the substrate surface, but intermediate compounds (borides) form between the substrate and boron, making separation difficult and reducing product purity

Engineering Contradiction:
Improveboron deposition rateVSAvoidproduct purity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention extracts the problematic metallic substrate from the system and replaces it with a quartz glass substrate. This removal eliminates the source of intermediate compound formation while maintaining the boron deposition capability, thereby resolving the contradiction between productivity and product purity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces quartz glass as an intermediary substrate material that does not form intermediate compounds with boron. This intermediary substrate enables boron deposition while preventing the formation of problematic boride layers, allowing for easy separation and high-purity product recovery.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If conventional heating methods are used in CVD reactors, then boron deposition can occur, but temperature distribution becomes non-homogeneous, affecting deposition uniformity

Engineering Contradiction:
Improvedeposition rateVSAvoidtemperature distribution uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The heating system is segmented into multiple independent heating zones along the reactor tube, each controlled separately. This segmentation allows for precise temperature control and uniform heat distribution throughout the deposition area, eliminating hot spots and cold zones that would otherwise affect deposition uniformity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention implements local quality control by providing different heating intensities at different positions along the reactor tube. The heating elements are arranged to create a homogeneous temperature field in the deposition zone, ensuring uniform boron deposition across the substrate surface.

Inventive Principle:
Principle #3Local quality

3Productivity

If high temperatures are used for rapid boron deposition, then production rate increases, but radiative energy losses to surroundings increase, reducing energy efficiency

Engineering Contradiction:
Improveboron production rateVSAvoidradiative energy loss
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The invention converts the harmful radiative energy loss into a beneficial effect by using the thermal radiation to preheat the incoming gas mixture and to maintain the temperature of reactor components. The high-temperature zone's radiative energy, which would otherwise be wasted, is utilized to improve overall energy efficiency while maintaining high deposition rates.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The invention optimizes the temperature profile along the reactor by creating a gradual temperature gradient rather than a uniform high temperature. This parameter change allows for rapid boron deposition in the high-temperature zone while reducing radiative losses in lower-temperature sections, improving energy efficiency without sacrificing production rate.

Inventive Principle:
Principle #35Parameter changes

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 design achieves high-purity, uniform elemental boron and advanced ceramic powders with improved production rates and reduced energy consumption by ensuring homogenous temperature distribution and easy separation from the substrate, resulting in higher yields and purer products.

Implementation Method 1

at least one heating element (3) which surrounds the inner tube (2) and enables to heat both the inner tube (2) and the gas passing therethrough

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

at least one reflector (5) which encompasses the outer tube (4) and whose surface facing the outer tube (4) is reflective

Methodology Applied
Scientific EffectThermal radiation reflection: Reflection

Implementation Method 3

A reactor designed for chemical vapor deposition method and method of producing elemental boron and advanced ceramic powders with this reactor

Methodology Applied
Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentEP2735544B1A reactor designed for chemical vapor deposition method and method of producing elemental boron and advanced ceramic powders with this reactor
Publication Date: 2020.09.30 ULUSAL BOR ARASTIRMA ENSTITUSU
  • EP2735544B1 patent drawingFigure 1~4
  • EP2735544B1 patent drawingFigure 5

AI summary

The invention relates to a reactor (1) designed for the chemical vapor deposition method employed in the production of elemental boron and advanced ceramic powders. The objective of the present invention is to provide a reactor design; which enables homogenous temperature distribution in the inner tube (2) where the reaction takes place thanks to its reflector (5), minimizes the energy losses occurring due to radiation; enables production of uniform, mono/multi-structured products in higher amounts compared to the conventional applications by means of the homogenous temperature distribution; and enables removal of the impurities in the product easily and completely; and to provide a production method for elemental boron and advanced ceramic powders by means of this reactor.