Quantum Well Photodiode Structure for Noise-Resistant Light Absorption
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Solution Overview
Problem
Solid-state photodiodes have limited sensitivity and power conversion efficiency for certain wavelengths of light, are affected by temperature, and are susceptible to noise, which limits their effectiveness in various applications.
Innovation Solution
The development of a photodiode device with a gallium and nitrogen containing substrate, featuring a super lattice defect mitigation layer, quantum well regions, and a light trapping structure comprising hexagonal pyramid structures and nanodots, which enhances light absorption and reduces electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional solid-state photodiode structure is used, then the device is simple to manufacture, but the sensitivity to certain wavelengths of light is limited and power conversion efficiency is reduced
Solution Approach 1:
The photodiode structure is segmented into multiple functional layers including a superlattice layer with alternating high and low barrier materials, multiple quantum well regions with different indium concentrations, and barrier layers. This segmentation allows each layer to be optimized for specific wavelength ranges, thereby improving overall sensitivity and power conversion efficiency across the blue and violet spectrum.
Solution Approach 2:
The patent employs composite material structures combining different III-nitride materials (GaN, InGaN) with varying indium concentrations to create the superlattice and quantum well regions. These composite structures enable tailored optical and electrical properties that enhance sensitivity to specific wavelengths while maintaining structural integrity and manufacturability.
2Temperature
If the photodiode operates at higher temperatures, then the device can operate in broader environmental conditions, but the power conversion efficiency is affected and accuracy is reduced
Solution Approach 1:
The patent optimizes key parameters including indium concentration gradients in quantum well regions (increasing from lower to higher indium content in successive wells), layer thicknesses, and doping profiles to enhance carrier multiplication efficiency. These parameter optimizations enable the device to maintain high power conversion efficiency across broader temperature ranges by improving the fundamental physics of carrier generation and transport.
3Measurement precision
If conventional photodiode structures are used, then the device is compact, but susceptibility to noise is increased and accuracy is reduced
Solution Approach 1:
The superlattice layer acts as an intermediary structure between the substrate and the quantum well regions, providing defect mitigation and improving crystal quality. Additionally, the carefully designed barrier layers with graded indium concentrations serve as intermediaries that optimize carrier transport while filtering out noise, thereby improving signal-to-noise ratio and measurement accuracy.
4Productivity
If more quantum well regions are added to improve light absorption, then the power conversion efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent implements a periodic superlattice structure with alternating high and low barrier layers, and multiple quantum well regions arranged in a systematic pattern. This periodic structure enables efficient light absorption across multiple wavelengths while maintaining a manageable number of layers through repetition of optimized unit cells, balancing performance improvement with manufacturing complexity.
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 device achieves improved sensitivity, immunity to electromagnetic noise, and high power conversion efficiency, enabling efficient optical energy conversion and data transmission.
Implementation Method 1
a super lattice (SL) indium gallium nitrogen as a defect mitigation layer containing material overlying the N-type gallium and nitrogen containing material
Implementation Method 2
A solid-state photodiode is a semiconductor device that converts light into an electrical signal. It is made of a p-n junction with a depletion region that generates a current when light is absorbed by the device.
Implementation Method 3
a plurality of hexagonal shaped pyramid structures spatially disposed along the backside surface... configured to enhance an absorption of the radiation into the active region
Data Source
AI summary
The present invention relates to techniques, including methods and devices, for optical technology. In particular, the present invention provides methods, devices, and structures for optical devices, and in particular, photo diodes, commonly called photo sensors.