Buried Ridge Semiconductor Laser for High-Temperature Electron Blocking
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Solution Overview
Problem
The existing optical semiconductor devices face issues with carrier absorption and inter-valence-band absorption due to the collapse of the modulation-doped structure, leading to optical loss and performance degradation, particularly at high temperatures, where the p-type InP layer is not in contact with the side surfaces of the active layer, resulting in insufficient energy barriers for electron current and potential overflow.
Innovation Solution
A semiconductor laser with a ridge structure that includes an n-type cladding layer, an active layer, and a p-type cladding layer, where the buried layer covers both sides of the ridge structure and features a p-type semiconductor layer in contact with both side surfaces of the p-type cladding and active layers, but not with the n-type cladding layer, forming an energy barrier to prevent electron overflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the p-type InP layer is not in contact with the side surfaces of the active layer to prevent modulation-doped structure collapse, then optical loss due to carrier absorption is reduced, but the energy barrier for electron current becomes insufficient causing electron overflow at high temperatures
Solution Approach 1:
The patent introduces an Fe-doped InP layer as an intermediary between the p-type InP layer and the active layer. This intermediary layer serves dual purposes: it prevents direct contact between the p-type InP layer and active layer (avoiding modulation-doped structure collapse and carrier absorption), while simultaneously providing the necessary energy barrier to contain electron current and prevent overflow at high temperatures.
2Reliability
If the p-type InP layer contacts the side surfaces of the active layer to provide energy barrier, then electron overflow is prevented, but carrier absorption increases causing optical loss
Solution Approach 1:
The Fe-doped InP layer acts as a mediator that enables the p-type InP layer to provide energy barrier function without directly contacting the active layer. This indirect contact arrangement maintains electron current containment while preventing the harmful carrier absorption that would occur with direct contact.
3Reliability
If zinc dopant diffuses into the Fe-doped InP layer, then the Fe-doped InP layer ceases to function as high-resistance layer, but maintaining doping structure increases complexity
Solution Approach 1:
The Fe-doped InP layer serves as a protective intermediary that shields the zinc dopant in the p-type InP layer from diffusing into the active layer. By positioning this layer between the doped region and the active layer, the patent prevents dopant migration while maintaining a relatively simple overall doping structure.
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 configuration reduces reactive currents that do not pass through the active layer, enhancing optical output characteristics and high-speed operation performance, particularly at high temperatures by preventing electron overflow.
Implementation Method 1
the p-type InP layer s10 has a function of preventing the electron current injected into the active layer s4 from overflowing due to heat and leaking from the side surfaces of the active layer s4 to the outside, that is, a function of an energy barrier with respect to the electrons
Data Source
AI summary
A semiconductor laser includes a ridge structure formed on an n-type semiconductor substrate, and a buried layer buried so as to cover both sides of the ridge structure opposed to each other in a direction perpendicular to an extending direction of the ridge structure. The ridge structure includes an n-type cladding layer, an active layer, and a p-type cladding layer formed sequentially from a side of the n-type semiconductor substrate. The buried layer includes a p-type semiconductor layer in contact with both side surfaces of the p-type cladding layer and the active layer in the ridge structure, and a semi-insulating layer, and the p-type semiconductor layer is not in contact with the n-type cladding layer of the ridge structure.