Semiconductor Optical Element Mesa Corner Protection
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Solution Overview
Problem
Wet etching in semiconductor optical elements often results in abnormal etching at corner parts of mesa structures, leading to undesired mesa formation and compromised properties of the semiconductor optical elements.
Innovation Solution
A method involving the formation of an extended mesa of the same material connected to the corner of the mesa structure, using a mask material patterning technique to prevent abnormal etching, where the wet etching is stopped before the epitaxial layer disappears, ensuring precise control over the mesa structure formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet etching is used to form mesa structure, then the etching can be stopped between two layers having different composition and crystal face can be formed, but abnormal etching proceeds in the corner part and desired mesa structure can't be formed
Solution Approach 1:
The patent applies preliminary action by forming a protective film on the corner parts of the mesa structure before performing wet etching. This protective film is applied in advance to prevent the abnormal etching that would otherwise occur at the corner parts during the etching process, thereby ensuring the desired mesa structure can be formed with proper dimensions and shape.
2Ease of manufacture
If wet etching is used to form mesa structure, then selective etching between layers can be achieved, but the corner part etching proceeds abnormally leading to compromised semiconductor optical element properties
Solution Approach 1:
The patent applies local quality by making the protective film's presence location-specific - it is applied only to the corner parts of the mesa structure rather than the entire surface. This localized protection allows the wet etching to proceed normally on the main surfaces while preventing abnormal etching only at the corner parts, thus maintaining selective etching capability while improving corner part dimensional accuracy.
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 effectively prevents abnormal etching at corner parts, allowing for the formation of desired mesa structures, thereby enhancing the yield and achieving the desired properties of semiconductor optical elements, such as the MMI optical coupler, by protecting the corner parts and maintaining design integrity.
Implementation Method 1
The mesa structure is formed by wet etching
Data Source
AI summary
A semiconductor optical element having a mesa structure formed by wet etching, includes a mesa structure having a ridge-type mesa structure or a high-mesa-type mesa structure, the mesa structure being disposed on a semiconductor substrate, and an extended mesa on the semiconductor substrate, the extended mesa being connected to a corner of the mesa structure and being the same material as the mesa structure.