GaN Mesa Substrate Porosity Levels for Multi-Wavelength Diode Arrays
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Solution Overview
Problem
The existing methods for manufacturing arrays of diodes that emit light at different wavelengths require complex steps, including localized dopant implantation, which complicates the process and is not efficiently simplified.
Innovation Solution
A growth substrate with mesas of different porosification levels, categorized as M(N), M(0), and M(n), where the doped layers are separated by non-porous insulation layers, allowing for epitaxy regrowth layers with varying lattice parameters, enabling diodes to emit or detect light at different wavelengths without the need for localized dopant implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If localized dopant implantation is performed to create mesas with different doping levels, then diodes can emit light at different wavelengths, but the manufacturing process becomes complex
Solution Approach 1:
The invention extracts the dopant implantation step from the manufacturing process. Instead of implanting dopants locally to create different doping levels, the patent uses a uniform doped layer combined with selective electrochemical porosification to achieve different relaxation rates and thus different emission wavelengths, eliminating the complex implantation process
Solution Approach 2:
The invention changes the parameter being controlled from doping level to porosification level. By controlling the degree of porosification (0%, partial, or full) of the doped layer during electrochemical treatment, different relaxation rates are achieved, which in turn enables different emission wavelengths without requiring different doping levels
2Adaptability or versatility
If multiple doping levels are introduced in different mesas, then native emission at different wavelengths is achieved, but the process requires complex localized implantation steps
Solution Approach 1:
The invention segments the doped layer into different porosification states (non-porous, partially porous, fully porous) across different mesas. This segmentation is achieved through selective electrochemical treatment rather than segmented dopant implantation, simplifying the manufacturing process while maintaining the ability to produce native emission at different wavelengths
Solution Approach 2:
The invention introduces porosification as an intermediary mechanism between the uniform doped layer and the final emission wavelength. The porosification level acts as a mediator that translates a uniform doping structure into diverse emission characteristics, avoiding the need for complex localized implantation
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 simplifies the manufacturing process by eliminating the need for localized dopant implantation and allows for the production of diodes that emit or detect light at different wavelengths, such as RGB colors, through a single electrochemical porosification step and epitaxy regrowth.
Implementation Method 1
making a growth substrate having several mesas made of InGaN, each formed by an InGaN doped layer made porous during an electrochemical porosification step
Implementation Method 2
an epitaxy regrowth layer resting on an upper doped layer amongst the N doped layers
Data Source
AI summary
A growth substrate adapted for making by epitaxy an array of InGaN based diodes, including mesas M(i), made of GaN based crystalline materials, each including N doped layers, with N≥2, separated in pairs by an insulation intermediate layer made of a non-porous material, and each having a free upper face adapted for making a diode of the array by epitaxy; the mesas being configured according to at least three different categories including: a so-called M(N) mesas category where the N doped layers are porous; a so-called M(0) mesas category where none of the doped layers (13, 15) is porous; and a so-called M(n) mesas category where n doped layers are porous, with 1≤n<N.