Downward Thermal Evaporation Source for Uniform Cu(InGa)Se2 Deposition

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Solution Overview

Problem

The challenge in vertical thermal evaporation of thin films, such as Cu(InGa)Se2, is that rigid substrates can only be supported at their edges, limiting substrate temperature and potentially the photovoltaic conversion efficiency of the deposited films.

Innovation Solution

The development of thermal evaporation sources that allow for downwards- or sideways-evaporating configurations, which enable substrates to be supported across their entire width, thereby allowing higher substrate temperatures and more uniform deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If vertical evaporation configuration is used, then device simplicity is improved, but substrate temperature is limited due to edge-only support requirements

Engineering Contradiction:

Improveevaporation source designVSAvoidsubstrate temperature

Core Design Contradiction:

Device complexityVSTemperature

Solution Approach 1:

The patent inverts the conventional vertical evaporation configuration by implementing downward evaporation where the substrate is positioned above the evaporation source rather than below. This inversion allows the substrate to be supported from below across its entire surface area, eliminating the edge-only support constraint and enabling higher substrate temperatures without warpage or breakage of rigid substrates like glass

Inventive Principle:

Principle #13The other way round (Inversion)

2Manufacturing precision

If substrate is supported at edges only, then shadowing and surface marring are avoided, but substrate temperature is limited

Engineering Contradiction:

Improvesubstrate surface qualityVSAvoidsubstrate temperature

Core Design Contradiction:

Manufacturing precisionVSTemperature

Solution Approach 1:

By inverting the evaporation configuration to downward evaporation, the substrate support problem is fundamentally changed. Instead of edge-only support from below, the substrate can now be supported across its entire surface from below, eliminating temperature limitations while maintaining surface quality through proper support design that avoids shadowing

Inventive Principle:

Principle #13The other way round (Inversion)

3Temperature

If downward evaporation configuration is used, then substrate temperature can be increased, but device complexity increases

Engineering Contradiction:

Improvesubstrate temperatureVSAvoidevaporation source design

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The inversion to downward evaporation configuration enables full-surface substrate support and higher temperatures. The increased device complexity is managed through a modular design that maintains the essential evaporation function while adding the capability for enhanced substrate support and temperature control

Inventive Principle:

Principle #13The other way round (Inversion)

4Productivity

If high substrate temperature is used, then photovoltaic conversion efficiency is improved, but substrate warpage or breakage risk increases

Engineering Contradiction:

Improvephotovoltaic conversion efficiencyVSAvoidsubstrate integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The downward evaporation configuration with full-surface substrate support fundamentally changes the thermal-mechanical stress distribution. The substrate can now withstand high temperatures required for optimal photovoltaic conversion efficiency without the warpage or breakage risks associated with edge-only support, as the distributed support prevents localized stress concentration

Inventive Principle:

Principle #13The other way round (Inversion)

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

These configurations allow for higher substrate temperatures, improved deposition uniformity, and increased photovoltaic conversion efficiency of Cu(InGa)Se2 absorber layers, while also reducing the risk of substrate warpage or breakage.

Implementation Method 1

a heater capable of heating some or all of the thermal evaporation source to a temperature sufficient to produce the one or more evaporant vapor flows

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

one or more effusion nozzles flowably connected to the expansion chamber and exiting an outer surface of the thermal evaporation source, the nozzle(s) oriented to direct an evaporant vapor flow out of the source

Methodology Applied

Scientific EffectEffusion: Effusion

Implementation Method 3

The high-vacuum deposition of thin films, such as Cu(InGa)Se2, by thermal evaporation onto horizontally-oriented substrates

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Data Source

PatentUS12286704B2Thermal evaporation sources for wide-area deposition

Publication Date: 2025.04.29 JLN SOLAR

AI summary

A thermal evaporation sources are described. These thermal evaporation sources include a crucible configured to contain a volume of evaporant and a vapor space above the evaporant.