GaN Substrate Bonding for Blue Green Laser Efficiency
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Solution Overview
Problem
Current laser technologies for blue and green wavelengths are inefficient, large, expensive, and fragile, with challenges in modulating at high speeds due to energy storage properties and sensitivity to temperature, limiting their broader deployment.
Innovation Solution
The method involves fabricating optoelectronic devices using nonpolar or semipolar gallium-containing substrates like GaN, AlN, and InGaN, bonding multiple small-area semiconductor wafers to a carrier wafer for parallel processing, and aligning crystallographic directions to optimize device performance, enabling cost-effective manufacturing of blue and green laser devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lamp pumped solid state lasers are used for blue and green wavelengths, then laser output is achieved, but wall plug efficiency is extremely low (around 1%) and the system is large and expensive
Solution Approach 1:
The patent replaces the mechanical lamp pumping system with a semiconductor diode pumping system. The diode laser directly pumps the gain crystal, eliminating the need for inefficient lamp excitation and multiple optical conversion stages, thereby dramatically improving wall plug efficiency while reducing system size and complexity
Solution Approach 2:
The patent changes the pumping wavelength parameter from broad-spectrum lamp output to specific 808 nm diode laser wavelength, which matches the absorption peak of the gain crystal. This parameter optimization enables direct and efficient energy transfer, resolving the efficiency problem while simplifying the optical system
2Use of energy by moving object
If diode pumped solid state lasers are used to improve efficiency, then wall plug efficiency increases to 5-10%, but system cost increases and precise temperature control is required
Solution Approach 1:
The patent selects specific laser diode parameters (808 nm wavelength, appropriate power levels) that match the gain crystal's absorption characteristics. This parameter optimization maximizes pumping efficiency while minimizing the need for complex temperature control systems, making the system more manufacturable and cost-effective
Solution Approach 2:
The patent uses commercially available 808 nm laser diodes that are already optimized for pumping common gain crystals like Nd:YAG. By copying proven diode designs and configurations, the system avoids development costs and leverages existing manufacturing infrastructure, reducing overall system cost
3Reliability
If gain crystal with energy storage properties is used, then laser oscillation is achieved, but high-speed modulation becomes difficult
Solution Approach 1:
The patent introduces dynamic control of the pump diode current to actively manage the energy storage in the gain crystal. By modulating the pump power in real-time, the system can extract energy faster than passive storage allows, enabling high-speed modulation while maintaining stable oscillation through active energy management
4Use of energy by moving object
If directly doubled diode lasers are used for blue and green output, then efficiency and cost are improved, but severe temperature sensitivity limits application
Solution Approach 1:
The patent introduces a frequency doubling crystal as an intermediary between the infrared diode laser and the visible output. This crystal converts the 1064 nm diode output to 532 nm green light, allowing the use of temperature-stable infrared diodes while achieving visible wavelengths, thereby reducing temperature sensitivity compared to direct blue/green diodes
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 results in a cost-effective, efficient, and stable optical device capable of emitting blue and green laser light, overcoming the inefficiencies and fragilities of existing technologies by aligning crystallographic directions and using parallel processing techniques.
Implementation Method 1
a laser diode device that includes a gallium and nitrogen containing substrate... capable of emitting blue and green laser light
Implementation Method 2
bonding multiple small-area semiconductor wafers to a carrier wafer for parallel processing
Data Source
AI summary
In an example, the present invention provides a gallium and nitrogen containing structure. The structure has a plurality of gallium and nitrogen containing semiconductor substrates, each of the gallium and nitrogen containing semiconductor substrates having one or more epitaxially grown layers. The structure has a first handle substrate coupled to each of the substrates. The orientation of a reference crystal direction for each of the substrates are parallel to within 10 degrees or less. The structure has a first bonding medium provided between the first handle substrate and each of the substrates.