GaN Laser Diode Gettering Region for Blue Green Light
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Solution Overview
Problem
Current laser diode technologies face inefficiencies and challenges in producing blue and green laser light, particularly due to high sensitivity to temperature and energy storage properties, which limit their modulation speed and broader deployment.
Innovation Solution
A gallium and nitrogen containing laser diode device with a semi-polar oriented substrate and a p-type cladding region doped with magnesium, incorporating a gettering region to manage residual magnesium incorporation and improve optical mode confinement, reducing unwanted absorption and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional laser diode technologies are used to produce blue and green laser light, then laser output can be achieved, but high sensitivity to temperature and energy storage properties limit modulation speed and efficiency
Solution Approach 1:
The patent changes the crystal orientation parameter from conventional c-plane to semi-polar orientations (such as {20-21}, {11-20}, or {10-10} planes), which fundamentally alters the physical properties of the laser diode. This parameter change reduces temperature sensitivity and improves modulation speed by modifying the band structure and carrier transport characteristics inherent to the crystal orientation
2Reliability
If magnesium is doped into the p-type cladding region, then electrical performance is improved, but residual magnesium incorporation causes unwanted absorption and reduces efficiency
Solution Approach 1:
The patent segments the magnesium doping process by introducing a dedicated gettering layer (such as GaN or AlGaN) between the active region and the p-type cladding region. This gettering layer is specifically designed to absorb residual magnesium atoms during growth, preventing them from reaching the active region and causing optical absorption, while the p-type cladding region above the gettering layer maintains its necessary electrical properties
Solution Approach 2:
The gettering layer acts as an intermediary element between the magnesium-doped p-type cladding region and the active region. It mediates the conflict by selectively capturing residual magnesium atoms that would otherwise cause unwanted absorption in the active region, while allowing the p-type cladding to maintain its electrical functionality
3Productivity
If conventional c-plane substrates are used, then manufacturing is straightforward, but optical mode confinement and efficiency are limited
Solution Approach 1:
The patent changes the substrate crystal orientation parameter from conventional c-plane to semi-polar orientations, which improves optical mode confinement and overall device efficiency. While this requires updates to manufacturing processes, the patent maintains compatibility with existing epitaxial growth techniques, balancing manufacturing feasibility with performance improvement
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 solution enables improved efficiency and reduced sensitivity to temperature, allowing for more effective modulation and broader application of blue and green laser diodes by managing magnesium incorporation and optical mode confinement.
Implementation Method 1
a gettering region comprising a magnesium species overlying the surface region
Implementation Method 2
improve optical mode confinement, reducing unwanted absorption and enhancing efficiency
Data Source
AI summary
In an example, the present invention provides a gallium and nitrogen containing laser diode device. The device has a gallium and nitrogen containing substrate material comprising a surface region, which is configured on either a ({10-10}) crystal orientation or a {10-10} crystal orientation configured with an offcut at an angle toward or away from the [0001] direction. The device also has a GaN region formed overlying the surface region, an active region formed overlying the surface region, and a gettering region comprising a magnesium species overlying the surface region. The device has a p-type cladding region comprising an (InAl)GaN material doped with a plurality of magnesium species formed overlying the active region.