Semiconductor Layer Separation via Selective Chemical Etching
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Solution Overview
Problem
The manufacturing of nitride semiconductor thin films for light emitting elements is hindered by the high cost of sapphire substrates and the presence of lattice defects in the epitaxial layers obtained through conventional laser lift-off methods, which limits the production of high-efficiency light emitting elements.
Innovation Solution
A method involving epitaxial growth of semiconductor layers on a substrate, followed by patterning and selective etching using specific etchants to separate the semiconductor layer from the substrate without applying physical force, allowing for the formation of high-quality thin-film semiconductor elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the laser lift-off method is used to separate the nitride semiconductor layer from the sapphire substrate, then the thin-film semiconductor layer can be obtained, but lattice defects are introduced into the epitaxial layer
Solution Approach 1:
The invention extracts the nitride semiconductor layer from the sapphire substrate through chemical etching of the substrate rather than mechanical separation. The etchant selectively removes the sapphire substrate material while leaving the epitaxial layer intact, thereby obtaining the thin-film semiconductor layer without introducing lattice defects that would compromise light-emitting efficiency.
Solution Approach 2:
The invention introduces an intermediary chemical etching process between the epitaxial growth and the final product. Instead of directly separating the layer from the substrate through laser irradiation, a chemical etchant acts as an intermediary to selectively remove the substrate material, preserving the crystalline structure of the epitaxial layer.
2Ease of manufacture
If the sapphire substrate is used as the base-material substrate for epitaxial growth, then the nitride semiconductor layer can be grown, but the substrate cost increases
Solution Approach 1:
The invention replaces the expensive sapphire substrate with a cheaper alternative substrate that serves the same functional purpose during epitaxial growth. The cheaper substrate is used temporarily during the growth process and then completely removed through selective chemical etching, eliminating the need to purchase and reuse expensive sapphire substrates.
Solution Approach 2:
The invention changes the material parameter of the substrate from expensive sapphire to a cheaper alternative material that can be selectively etched. This parameter change allows the substrate to fulfill its temporary role during epitaxial growth while enabling cost-effective disposal through chemical etching rather than requiring expensive substrate reuse.
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 method enables the production of high-quality semiconductor thin films without the need for expensive substrates and reduces lattice defects, resulting in reliable semiconductor elements with improved light emitting efficiency.
Implementation Method 1
removing a portion of the semiconductor layer other than the patterned portion by a first etching method with a first etchant
Implementation Method 2
immersing a resultant from the first etching method in a second etchant that etches only the semiconductor substrate by a second etching method thereby removing the substrate from the semiconductor layer
Implementation Method 3
growing epitaxially a semiconductor layer on top of a semiconductor substrate
Data Source
AI summary
An aspect of the invention provides a method of manufacturing a method of manufacturing a semiconductor element comprises the steps of: growing epitaxially a semiconductor layer on top of a semiconductor substrate; forming a patterned portion of the grown semiconductor layer by forming a pattern by a patterning process on top of the grown semiconductor layer; removing a portion of the semiconductor layer other than the patterned portion by a first etching method with a first etchant; and immersing a resultant from the first etching method in a second etchant that etches only the semiconductor substrate by a second etching method thereby removing the substrate from the semiconductor layer.