Thin InGaAsP Etch Stop Layer for InP Cross-Hatch Control
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Solution Overview
Problem
The existing methods for manufacturing semiconductor optical devices with InP growth substrates suffer from cross-hatch defects due to lattice mismatch between the etch stop layer and the substrate, leading to uneven dissolution and reduced output power.
Innovation Solution
A method involving the formation of an etch stop layer with a thickness of 100 nm or less, preferably 50 nm or less, using InGaAsP-based III-V group compound semiconductor layers, which are lattice-matched to the InP substrate, to prevent cross-hatch formation and ensure complete substrate dissolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the etch stop layer is made thick to prevent complete dissolution during substrate removal, then the etch stop layer remains intact during etching, but cross-hatch defects develop due to strain energy accumulation
Solution Approach 1:
The patent changes the thickness parameter of the etch stop layer from conventional thick designs to a specific thin range (5-50 nm). This parameter change prevents strain energy accumulation that causes cross-hatch defects while maintaining sufficient etch stop functionality during substrate removal
Solution Approach 2:
The patent applies a locally optimized etch stop layer thickness specifically at the interface between the InP growth substrate and the semiconductor laminate. This localized thinning prevents cross-hatch at the critical interface while maintaining overall device structure integrity
2Object-affected harmful factors
If the etch stop layer is made thin to prevent cross-hatch, then cross-hatch defects are prevented, but the etch stop layer may dissolve completely during substrate removal
Solution Approach 1:
The patent identifies and applies a critical thickness range (5-50 nm) for the etch stop layer. Within this range, the layer is thin enough to prevent cross-hatch defect formation but thick enough to resist complete dissolution during the substrate removal process
Solution Approach 2:
The patent applies a minimal sufficient thickness of the etch stop layer - just enough to prevent complete dissolution during etching, but no more than necessary to avoid cross-hatch defects. This optimized thickness represents the partial action principle where only the minimum required function is provided
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 prevents cross-hatch defects and enhances the output power of semiconductor optical devices by maintaining the etch stop layer's integrity during substrate removal, improving the uniformity and efficiency of the manufacturing process.
Implementation Method 1
the etch stop layer having a thickness of 100 nm or less... InGaAsP-based III-V group compound semiconductor layers comprising at least In and P
Implementation Method 2
the InP growth substrate is immersed into an etching solution for a long time so that it is dissolved in the solution
Data Source
AI summary
A method of manufacturing a semiconductor optical device of this disclosure includes the steps of forming an etch stop layer on an InP growth substrate, the etch stop layer having a thickness of 100 nm or less; and forming a semiconductor laminate on the etch stop layer by stacking a plurality of InGaAsP-based III-V group compound semiconductor layers containing at least In and P. Further, an intermediate article of a semiconductor optical device of the present disclosure includes an InP growth substrate; an etch stop layer formed on the InP growth substrate, the etch stop layer having a thickness of 100 nm or less; and a semiconductor laminate formed on the etch stop layer, including a plurality of InGaAsP-based III-V group compound semiconductor layers containing at least In and P stacked one another.