Light-Emitting Structure With Separation Groove for Faster Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light-emitting devices used in optical communication face challenges in improving modulation speed and high-frequency characteristics due to parasitic capacitance at electrodes and wiring lines.
Innovation Solution
A light-emitting device with a stack structure featuring a separation groove and a high resistance region is designed, where the separation groove is symmetrically provided around the light emission section, and a high resistance region with higher electrical resistance than the emission section is incorporated on the outer side of the groove, reducing parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional light-emitting device structure is used, then the device is simple in structure, but parasitic capacitance at electrodes and wiring lines increases, degrading high-frequency characteristics
Solution Approach 1:
The device structure is segmented by introducing a separation groove that divides the semiconductor layer into a light emission section and a high resistance region. This segmentation electrically isolates the electrode and wiring line from the active region, reducing parasitic capacitance and improving high-frequency characteristics while maintaining manageable structural complexity
Solution Approach 2:
Different regions of the semiconductor layer are given different electrical properties: the light emission section maintains low resistance for efficient current injection, while the high resistance region (created by the separation groove and higher resistance semiconductor layer) provides electrical isolation. This local differentiation of electrical quality reduces parasitic capacitance without compromising overall device performance
2Speed
If the modulation speed is to be improved, then the CR time constant must be reduced, but this requires reducing parasitic capacitance which increases structural complexity
Solution Approach 1:
The separation groove segments the device structure to electrically isolate the high-frequency signal path from parasitic capacitance sources. By dividing the semiconductor layer into distinct functional regions, the design reduces the CR time constant and enables higher modulation speeds while keeping the structural additions minimal and targeted
Solution Approach 2:
The separation groove extracts or removes the parasitic capacitance problem by creating a physical and electrical barrier between the electrode/wiring line and the active region. This extraction of the harmful capacitive coupling effect allows for improved modulation speed without requiring complete redesign of the entire device 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 design effectively reduces parasitic capacitance, leading to improved high-frequency characteristics such as increased modulation speed by minimizing the CR time constant.
Implementation Method 1
The active layer performs light emission by current injection
Implementation Method 2
The high resistance region has electrical resistance higher than that of the light emission section
Data Source
AI summary
Provided is a light-emitting device that includes a light emission section, a separation groove, and a high reflectance region. The light emission section includes a stack structure including an active layer, a first reflector, and a second reflector. The active layer performs light emission by current injection. The first reflector and the second reflector are stacked in a first direction with the active layer interposed therebetween. The separation groove is provided symmetrically around the light emission section on an emission surface of light from the stack structure in the first direction. The separation groove is dug in the stack structure in the first direction. The high resistance region is provided in the stack structure on the outer side of an outermost shape of the separation groove on the emission surface. The high resistance region has electrical resistance higher than that of the light emission section.