Semipolar GaN Laser Diode Chip Size Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current laser technologies for blue and green wavelengths are inefficient, large, expensive, and fragile, with high sensitivity to temperature, limiting their broader deployment and application.
Innovation Solution
The use of semipolar gallium and nitrogen containing substrates, such as GaN, AlN, InN, InGaN, and AlGaN, in optical devices like laser diodes, which employ etched facets and p-down bonding to reduce chip size and cost, enabling efficient production and high-yield manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional laser technologies (Ar-ion gas lasers, LPSS-SHG, DPSS-SHG) are used for blue and green wavelengths, then laser output can be achieved, but wall plug efficiency remains low (1-10%), device size is large, cost is high, and temperature sensitivity is high
Solution Approach 1:
The patent extracts and eliminates the intermediate frequency conversion crystal stage from the traditional three-stage laser system. By using direct bandgap semiconductor materials (InGaN, AlGaN) that can directly emit blue/green light, the system removes the 1064nm laser crystal and SHG crystal, achieving wall plug efficiency >50% while reducing device size and complexity
Solution Approach 2:
The patent changes the fundamental material parameter from indirect bandgap (traditional laser crystals) to direct bandgap semiconductor materials. This parameter change enables direct light emission at blue/green wavelengths without frequency conversion, dramatically improving efficiency from 1-10% to >50% and simplifying the device structure
2Use of energy by moving object
If lamp pumped solid state lasers are used, then red and infrared wavelengths can be achieved with improved efficiency, but blue and green wavelengths remain challenging and require complex frequency conversion systems
Solution Approach 1:
The patent extracts the frequency conversion crystal and intermediate laser stage from the system. By using direct bandgap semiconductor materials that naturally emit blue/green light, the complex three-stage system (lamp→1064nm crystal→SHG crystal→visible) is reduced to a single efficient stage (electricity→semiconductor→visible), achieving >50% efficiency and simplifying manufacturing
Solution Approach 2:
The patent uses composite semiconductor material structures (InGaN quantum wells embedded in AlGaN barriers) to achieve direct blue/green light emission. This composite material approach enables high efficiency (>50%) and simplified manufacturing by eliminating the need for separate frequency conversion components
3Use of energy by moving object
If diode pumped solid state lasers with SHG are used, then wall plug efficiency improves to 5-10%, but system cost increases, temperature control requirements increase, and device size remains substantial
Solution Approach 1:
The patent removes the temperature-sensitive frequency conversion crystal and intermediate laser stage. By using direct bandgap semiconductor materials that emit blue/green light directly, the system achieves >50% efficiency without the temperature control complexities inherent in DPSS-SHG systems
Solution Approach 2:
The patent changes from indirect bandgap materials (requiring frequency conversion and temperature control) to direct bandgap semiconductor materials. This parameter change enables direct blue/green emission with >50% efficiency and reduced temperature sensitivity
4Device complexity
If directly doubled diode lasers are used, then efficiency and modularity improve, but severe temperature sensitivity limits application
Solution Approach 1:
The patent uses composite semiconductor structures (InGaN quantum wells in AlGaN barriers) with optimized composition ratios. This material composition approach achieves direct blue/green emission with improved thermal stability and >50% efficiency, reducing the severe temperature sensitivity of earlier diode designs
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 cost-effective, efficient, and compact optical devices capable of emitting electromagnetic radiation in the desired wavelengths, with improved modularity and reduced sensitivity to temperature, facilitating broader applications.
Implementation Method 1
a gallium and nitrogen containing optical device operable as a laser diode
Implementation Method 2
a chip formed from the gallium and nitrogen substrate member
Data Source
AI summary
Gallium and nitrogen containing optical devices operable as laser diodes and methods of forming the same are disclosed. The devices include a gallium and nitrogen containing substrate member, which may be semipolar or non-polar. The devices include a chip formed from the gallium and nitrogen substrate member. The chip has a width and a length, a dimension of less than 150 microns characterizing the width of the chip. The devices have a cavity oriented substantially parallel to the length of the chip.