Semiconductor Laser Ridge Structure for Leakage Path Control
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Solution Overview
Problem
Conventional semiconductor laser devices face challenges in controlling the etching process to reduce the width of the hole leakage path and electron leakage, leading to increased operating current and reduced reliability due to non-uniform etching and potential electron leakage through the n-type blocking layer.
Innovation Solution
A method involving laminated structures with selective etching and buried layers to form a ridge with a current constricting window, reducing the width of the hole leakage path and minimizing electron leakage by precise control of etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the upper face portion of the p-type cladding layer is etched to reduce the width of the hole leakage path, then the operating current can be reduced, but etching cannot be stopped with good controllability and it is difficult to leave the p-type cladding layer with a desired thickness
Solution Approach 1:
An InGaAsP cap layer is introduced as an intermediary layer between the p-type cladding layer and the mask. This cap layer has different etching characteristics, allowing the etching process to be stopped precisely when reaching the cap layer, thereby providing good controllability over the thickness of the remaining p-type cladding layer while reducing the hole leakage path width
Solution Approach 2:
The InGaAsP cap layer is formed in advance before the etching process. This preliminary action creates a distinct etching stop layer that enables precise control during subsequent etching, ensuring the p-type cladding layer is etched to the desired thickness without over-etching
2Object-generated harmful factors
If the upper face portion of the p-type cladding layer is etched, then the hole leakage path width is reduced, but a buried layer near the p-type cladding layer is simultaneously etched, so that the bottom face of the tip end of the n-type blocking layer comes closer to the active layer, increasing electron leakage
Solution Approach 1:
The InGaAsP cap layer acts as a protective intermediary that shields the buried layer from etching. By stopping the etching process when the cap layer is reached, the buried layer remains intact, maintaining its function as an electron barrier while still allowing hole leakage reduction through the etched p-type cladding layer
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 effectively reduces electron leakage and operating current, enhancing the reliability and optical output of semiconductor laser devices by maintaining precise thicknesses and minimizing electron leakage paths.
Implementation Method 1
a second buried layer forming step in which the second buried layer of the first conductivity type is grown so as to cover the ridge and the first buried layer
Data Source
AI summary
The present application is provided with: a ridge laminated with a first conductivity type cladding layer, an active layer, and a second conductivity type first cladding layer in order and having a top portion formed to be flat; a first buried layer buried on both side areas of the ridge; a second buried layer covering the first buried layer and protruding toward the center of the ridge and toward a top portion of the ridge to form an opening formed by protruding portions facing each other; and a second conductivity type second cladding layer buried on the second buried layer and in the opening, wherein a surface of the second buried layer on a side to the top portion of the ridge is formed so as to fit within a surface of the second conductivity type first cladding layer.