Front-Side Emitting Mid-Infrared LED Fabrication
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Solution Overview
Problem
Conventional semiconductor fabrication methods for light emitting diodes (LEDs) cannot be directly applied to antimonide-arsenide heterostructures for mid-infrared wavelength range due to differences in semiconductor material properties, limiting the development of front-side emitting mid-infrared LEDs compatible with high-brightness LED packages.
Innovation Solution
The development of specific fabrication processes for antimonide-arsenide semiconductor-based mid-infrared LEDs, including epitaxial growth of heterostructures, frontside lithographic processing for light extraction and current spreading, and backside processing for internal reflection and packaging, enabling the creation of high-brightness LEDs that emit light in the 3 to 20 μm wavelength range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional semiconductor fabrication methods are used, then LEDs can be manufactured for ultraviolet, visible, and near-infrared ranges, but these methods cannot be applied to antimonide-arsenide heterostructures for mid-infrared wavelength range
Solution Approach 1:
The patent modifies fabrication process parameters including epitaxial growth conditions, lithographic patterns, and metal layer configurations to accommodate antimonide-arsenide heterostructures. Specific changes in growth temperature, pressure, and composition ratios enable mid-infrared emission while maintaining manufacturing feasibility
Solution Approach 2:
The invention creates a unified fabrication methodology that serves multiple wavelength ranges by adapting core processes rather than developing entirely separate manufacturing flows. The same basic epitaxial growth and lithographic techniques are universalized across different semiconductor material systems through parameter adjustment
2Illumination intensity
If light extraction features are added to increase light output, then more light can escape the die, but the fabrication process becomes more complex
Solution Approach 1:
The patent combines light extraction features with existing lithographic patterning steps for electrical contacts. The same lithographic masks and etching processes that define contact regions also create light extraction structures, merging two functions into a single fabrication sequence rather than requiring separate processing steps
Solution Approach 2:
Light extraction features are selectively implemented in specific regions of the die where they provide maximum benefit. The features are localized to areas with appropriate optical and electrical characteristics, applying complexity only where needed rather than uniformly across the entire device structure
3Illumination intensity
If substrate is thinned to improve light extraction and reduce absorption, then optical performance improves, but mechanical strength and handling become more difficult
Solution Approach 1:
The substrate thinning is performed early in the fabrication process before subsequent processing steps. By reducing substrate thickness beforehand, the patent minimizes light absorption and improves extraction efficiency for all subsequent epitaxial layers and optical features, rather than requiring final thinning after device assembly
Solution Approach 2:
The patent employs composite substrate structures or supports that provide mechanical strength while allowing optical transparency. Thinned substrates are combined with support layers or mounting structures that restore mechanical integrity while maintaining optical performance in the mid-infrared range
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 allows for the production of mid-infrared LEDs that are compatible with standard LED packaging and drive systems, enabling applications in chemical detection, communication, night vision, and thermal imaging by adjusting layer thicknesses and light extraction features to achieve desired wavelengths.
Implementation Method 1
as electrical current is applied to the junctions, electrons and holes combine with each other and emit photons. The energy contained in the emitted photons corresponds to the energy difference between the respective holes and electrons
Implementation Method 2
coating the surface with a metal layer sequence which simultaneously forms an internal mirror
Implementation Method 3
the fabrication can include a process for lithographically patterning the epitaxial and other layers to define electrical contacts
Implementation Method 4
the fabrication process can include processes for the epitaxial growth of light emitting and other semiconductor layers on a substrate
Data Source
AI summary
Methods for fabricating mid-infrared light emitting diodes (LEDs) based upon antimonide-arsenide semiconductor heterostructures and configured into front-side emitting high-brightness LED die and other LED die formats.