Indium Aluminum Phosphide Release Layer for Semiconductor Transfer

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Solution Overview

Problem

Existing methods for releasing compound semiconductor devices from substrates face challenges such as poor stability of release layers in air, difficulty in protecting sensitive device surfaces from etching chemicals, and incompatibility with micro-transfer printing, especially for devices with aluminum-containing layers or dielectrics.

Innovation Solution

A method involving a release layer of indium aluminum phosphide (InAlP) with a support layer, where the InAlP layer is selectively etched using a hydrochloric acid and ethanol solution, providing etching selectivity and stability, and allowing for the release of devices with high aspect ratios and sensitive materials without damaging them.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If hydrofluoric acid-based wet etches are used as release agents, then etching selectivity is achieved, but device surfaces cannot be protected from etching damage

Engineering Contradiction:

Improveetching selectivityVSAvoidetching damage to device surfaces

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary protective layer comprising at least one of a polymer or a glassy carbon layer between the hydrofluoric acid-based wet etch and the device surface. This intermediary layer allows the etch to selectively remove the release layer while protecting sensitive device surfaces from etching damage, thus resolving the contradiction between achieving etching selectivity and preventing surface damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If thick polymeric coatings are used to protect device surfaces, then etching protection is achieved, but device complexity increases

Engineering Contradiction:

Improveetching protectionVSAvoidcoating thickness requirements

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent changes the parameter of protective layer thickness from thick (>20 micron) to thin (5-200 nanometer), achieving effective etching protection while minimizing device complexity. The protective layer comprises at least one of a polymer or glassy carbon material applied in controlled thin layers that provide sufficient protection without excessive complexity.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If hydrofluoric acid-based etching is used, then release process effectiveness is achieved, but compatibility with micro-transfer printing is lost

Engineering Contradiction:

Improverelease process effectivenessVSAvoidcompatibility with micro-transfer printing

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent segments the release process into distinct functional layers: a release layer containing aluminum arsenide or indium aluminum phosphide that is selectively etched by hydrofluoric acid, and a separate protective layer that shields device surfaces. This segmentation allows the release process to remain effective while becoming compatible with micro-transfer printing by preventing damage to transfer-sensitive device surfaces.

Inventive Principle:

Principle #1Segmentation

4Manufacturing precision

If aluminum-containing release layers are used, then etching selectivity is improved, but stability in air deteriorates

Engineering Contradiction:

Improveetching selectivityVSAvoidair stability

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by depositing the protective layer (polymer or glassy carbon) on the device surface before the release etching process. This pre-applied protective layer prevents air exposure and oxidation of the aluminum-containing release layer during processing, maintaining both etching selectivity and air stability through advance protection.

Inventive Principle:

Principle #10Preliminary action

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 enables stable and efficient release of semiconductor devices with high etch rates and selectivity, facilitating the transfer of devices like photovoltaic cells and light-emitting diodes, while being compatible with encapsulation and micro-transfer printing techniques.

Implementation Method 1

the release layer is selectively etched without substantially etching the support layer and the substrate

Methodology Applied

Scientific EffectSelective etching:

Data Source

PatentUS9355854B2Methods of fabricating printable compound semiconductor devices on release layers

Publication Date: 2016.05.31 X DISPLAY CO TECH LTD

AI summary

A method of fabricating transferable semiconductor devices includes providing a release layer including indium aluminum phosphide on a substrate, and providing a support layer on the release layer. The support layer and the substrate include respective materials, such as arsenide-based materials, such that the release layer has an etching selectivity relative to the support layer and the substrate. At least one device layer is provided on the support layer. The release layer is selectively etched without substantially etching the support layer and the substrate. Related structures and methods are also discussed.