Trench Photodetector Structure for Higher Light Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Photodetectors in integrated circuits often fail to absorb incident light due to low sensitivity, resulting in a lack of electrical signal generation despite the presence of light.
Innovation Solution
The integration of dielectric structures within the photodetector, which promote total internal reflection, increasing the path length of photons within the photosensitive material and enhancing sensitivity by ensuring photons are reflected multiple times before absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the photodetector uses a simple structure without additional optical elements, then the device complexity is low, but the sensitivity to incident light is insufficient
Solution Approach 1:
The patent introduces a vertical dimension by stacking multiple photodetector layers with different bandgaps along the light propagation path. This multi-layer structure increases the effective absorption path length without significantly increasing the lateral footprint, thereby improving sensitivity while maintaining a compact integrated circuit form factor.
Solution Approach 2:
The patent employs composite material structures by combining multiple semiconductor layers with different bandgap energies (e.g., InGaAsP layers with varying compositions) to create a photodetector array that can detect different wavelengths. This composite approach enables broadband detection capability while maintaining integration within a single device structure.
2Reliability
If the photodetector absorbs less incident light, then the device structure remains simple, but the electrical signal generation is insufficient
Solution Approach 1:
The patent segments the photodetector into multiple functional layers, each optimized for detecting specific wavelength ranges. By dividing the detection function across multiple specialized layers rather than relying on a single complex layer, the patent achieves improved signal generation for broadband detection while keeping each individual layer's structure relatively simple and manufacturable.
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 significantly increases the likelihood of photon absorption, thereby enhancing the sensitivity of the photodetector and ensuring effective electrical signal generation from incident light.
Implementation Method 1
The integration of dielectric structures within the photodetector, which promote total internal reflection, increasing the path length of photons within the photosensitive material
Implementation Method 2
The photodetectors detect light and generate electrical signals indicative of the light
Data Source
AI summary
An integrated circuit includes a photodetector. The photodetector includes one or more dielectric structures positioned in a trench in a semiconductor substrate. The photodetector includes a photosensitive material positioned in the trench and covering the one or more dielectric structures. A dielectric layer covers the photosensitive material. The photosensitive material has an index of refraction that is greater than the indices of refraction of the dielectric structures and the dielectric layer.