GaN Optical Devices Using Laser Scribing Metallization
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Solution Overview
Problem
Conventional light bulbs dissipate most energy as heat, are unreliable due to thermal expansion, emit light over a broad spectrum, and are not directional, while laser technologies for blue and green wavelengths are inefficient, large, expensive, and fragile, limiting their deployment.
Innovation Solution
The use of nonpolar gallium-containing substrates like GaN for optical devices, such as lasers and LEDs, with a method involving laser scribing and metallization to create efficient, cost-effective devices that emit electromagnetic radiation at specific wavelengths, improving contact resistance and reducing voltage drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional light bulbs are used for lighting, then they provide broad spectrum illumination, but they dissipate more than 90% of energy as thermal energy and are unreliable due to thermal expansion and contraction
Solution Approach 1:
The patent replaces the thermal incandescence mechanism of conventional bulbs with electroluminescence in semiconductor materials. This substitution eliminates the thermal expansion and contraction issues that cause filament failure, while also dramatically reducing energy loss as heat since the light generation process is not dependent on thermal radiation.
Solution Approach 2:
The invention changes the operating parameters from thermal-based illumination to electrical excitation of semiconductor materials. By using forward-biased p-n junctions or quantum wells to generate light directly through electroluminescence, the system achieves higher reliability and lower energy dissipation compared to thermal incandescence.
2Use of energy by moving object
If lamp pumped solid state lasers are used for blue and green wavelengths, then they can produce visible light output, but they are inefficient, large, expensive, and fragile
Solution Approach 1:
The patent extracts and eliminates the intermediate frequency conversion stages from the laser system. Instead of using lamp-pumped solid state lasers with multiple conversion crystals, the invention directly generates blue and green light using semiconductor materials, removing the bulky and expensive frequency conversion components.
Solution Approach 2:
The invention applies the successful architecture of red and infrared diode lasers to the blue and green wavelength regime. By copying the simple, efficient diode laser design used at longer wavelengths and adapting it for shorter wavelengths using appropriate semiconductor materials, the system achieves high efficiency without the complexity of lamp-pumped systems.
3Duration of action of moving object
If diode pumped solid state lasers with SHG are used, then they improve the efficiency and life of lasers, but they increase system cost and require precise temperature controls
Solution Approach 1:
The patent replaces the diode-pumped solid state laser architecture with direct semiconductor laser or LED structures. This substitution eliminates the need for precise temperature control systems and complex pumping mechanisms, while maintaining long operational life through the inherent robustness of semiconductor devices.
4Device complexity
If directly doubled diode lasers are used, then they improve efficiency and reduce size, but they have severe sensitivity to temperature which limits their application
Solution Approach 1:
The patent applies local quality principles by using specific semiconductor material compositions and heterostructure designs that are optimized for different wavelength regions. By carefully engineering the bandgap and material properties at each layer of the device, the system achieves reduced temperature sensitivity while maintaining compact size and high efficiency.
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 approach results in cost-effective, efficient optical devices with improved contact resistance and lower voltage drop, enabling the production of lasers and LEDs with specific wavelengths like 400-520 nanometers, enhancing their reliability and directional capabilities.
Implementation Method 1
subjecting the backside region to a laser scribing process to form a plurality of scribe regions
Data Source
AI summary
A method for forming optical devices. The method includes providing a gallium nitride substrate member having a crystalline surface region and a backside region. The method also includes subjecting the backside region to a laser scribing process to form a plurality of scribe regions on the backside region and forming a metallization material overlying the backside region including the plurality of scribe regions. The method removes at least one optical device using at least one of the scribe regions.