Semiconductor Optical Mesa Etching for Critical Dimension Uniformity
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Solution Overview
Problem
Conventional methods face challenges in creating precise and uniform mesa structures in buried hetero-structure semiconductor lasers, particularly in maintaining critical dimension uniformity during the etching process.
Innovation Solution
A method involving the use of Br-based chemicals, specifically a mixture of bromide (Br) and hydrogen bromide (HBr), is employed to etch semiconductor layers, forming mesa structures with consistent gradients and minimal deviation from predetermined dimensions, using a combination of wet etching and patterned mask layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used to form mesa structures, then the etching process can be completed, but the critical dimension uniformity deteriorates with variations exceeding 0.1 μm
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition and ratios of the etchant mixture (bromide and hydrogen bromide in specific ratios with water), etching temperature, and etching time to achieve consistent etching rates that produce uniform critical dimensions within 0.1 μm variation
Solution Approach 2:
The patent uses a specifically formulated etchant mixture containing bromide, hydrogen bromide, and water as an intermediary chemical system to mediate the etching process, providing controlled and uniform material removal that achieves the required dimensional precision
2Manufacturing precision
If the etching process is extended to improve uniformity, then dimensional consistency improves, but the manufacturing time increases
Solution Approach 1:
The patent optimizes the etching process by adjusting parameters including the etchant composition (bromide to hydrogen bromide ratio), temperature, and time to achieve the desired uniformity within an acceptable time frame, balancing precision and productivity
3Ease of manufacture
If the etchant composition is simplified for ease of use, then the manufacturing process becomes easier, but the mesa structure precision deteriorates
Solution Approach 1:
The patent employs a multi-component etchant system with specific ratios of bromide, hydrogen bromide, and water, where the precise composition parameters are optimized to achieve both ease of manufacture and high precision critical dimension control within 0.1 μm variation
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
The method achieves mesa structures with critical dimension variations of less than 0.1 μm, ensuring precise and uniform fabrication of semiconductor optical devices.
Implementation Method 1
performing a first etching operation to remove portions of the first cladding layer and the active layer exposed through the patterned mask layer, thereby forming a mesa structure on the semiconductor substrate, wherein the first etching operation uses an etchant comprising Br-based chemicals
Data Source
AI summary
A method of fabricating a semiconductor optical device is provided. The method includes steps of: providing a semiconductor substrate having a first conductivity type; depositing a first cladding layer having the first conductivity type on the semiconductor substrate; depositing an active layer on the first cladding layer; depositing a second cladding layer having a second conductivity type on the active layer, wherein the second conductivity type is different from the first conductivity type; forming a patterned mask layer over the second cladding layer; and performing an etching operation to sequentially remove portions of the second cladding layer, the active layer and the first cladding layer exposed through the patterned mask layer, thereby forming a mesa structure on the semiconductor substrate, wherein the etching operation uses an etchant comprising Br-based chemicals.