Nitride Semiconductor Laser Capacitance Control
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Solution Overview
Problem
Nitride semiconductor laser devices with different structures have varying capacitances, leading to increased costs and reduced productivity in mass production due to the need for individual adjustments of high frequency superposition circuits, and they are difficult to discriminate based on pad electrode shapes for testing.
Innovation Solution
The use of low or high dielectric constant insulating films and equal pad electrode areas with distinct shapes to standardize capacitance and facilitate image recognition of different structures, along with electrically isolated pad electrodes and low reflection parts on the wafer, allows for uniform capacitance and structural differentiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If devices having different structures are fabricated from a single wafer to improve manufacturing efficiency, then productivity is improved, but the capacitance of the devices varies leading to increased cost and reduced productivity due to individual circuit adjustments
Solution Approach 1:
The patent applies parameter changes by modifying the dielectric constant of the insulating film to control device capacitance. By selecting insulating films with different dielectric constants (high-k or low-k materials), the capacitance of laser devices can be adjusted to match specific application requirements, thereby resolving the issue of varying capacitances in mass-produced devices and eliminating the need for individual circuit adjustments.
2Productivity
If devices having different structures are fabricated from a single wafer, then productivity is improved, but the devices become difficult to discriminate for testing purposes
Solution Approach 1:
The patent applies local quality by introducing distinct structural features at specific locations on the wafer. Different regions of the wafer are designed with varying insulating film thicknesses or dielectric constants, creating locally differentiated device characteristics that enable easy discrimination during testing while maintaining high manufacturing efficiency through batch processing.
3Reliability
If high frequency superposition circuits are adjusted for each laser device to handle varying capacitances, then device performance is optimized, but cost increases and productivity decreases
Solution Approach 1:
The patent resolves this contradiction by changing the capacitance parameter through selection of insulating films with different dielectric constants during the manufacturing process. This allows devices to be produced with predetermined capacitance values that match standard circuit requirements, eliminating the need for individual circuit adjustments and enabling true mass production while maintaining optimized performance.
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 reduces capacitance for improved response and noise reduction, increases electrostatic discharge withstand voltage, and simplifies the adjustment of high frequency superposition circuits, while enabling cost-effective mass production and easy discrimination of laser devices by structure.
Implementation Method 1
a low dielectric constant insulating film which is stacked above the upper cladding layer
Implementation Method 2
a high dielectric constant insulating film which is stacked above the upper cladding layer
Data Source
AI summary
A nitride semiconductor laser device is provided herein that is reduced in capacitance to have a better response. The nitride semiconductor laser device includes: an active layer; an upper cladding layer which is stacked above the active layer; a low dielectric constant insulating film which is stacked above the upper cladding layer; and a pad electrode which is stacked above the low dielectric constant insulating film.