Integrated Circuit Photodetector With Internal Reflection Trench
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Solution Overview
Problem
Photodetectors in integrated circuits often lack sensitivity due to inadequate absorption of incident light, leading to a failure in generating electrical signals 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, thereby enhancing the absorption and sensitivity of the photodetector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photodetectors are designed with conventional structures, then the device complexity is low, but the light absorption capability and sensitivity are insufficient
Solution Approach 1:
The patent implements nesting by placing dielectric structures (such as pillars or cavities) within the photosensitive material of the photodetector. These nested dielectric structures create multiple interfaces that promote total internal reflection, thereby increasing the optical path length within the photosensitive material and enhancing light absorption capability without significantly increasing overall device complexity.
Solution Approach 2:
The patent applies local quality by introducing dielectric structures with specific refractive indices at particular locations within the photodetector. The dielectric materials are strategically positioned to create optimal optical paths and reflection conditions only in the regions where light absorption is most effective, rather than uniformly modifying the entire photodetector structure.
2Reliability
If the path length of light in photosensitive material is increased, then the sensitivity is enhanced, but the device complexity increases
Solution Approach 1:
The patent employs self-service by utilizing the natural optical properties of the dielectric structures and photosensitive material interfaces to automatically create total internal reflection. The dielectric structures are designed with appropriate refractive indices and geometries that inherently guide light through multiple reflections without requiring external control mechanisms or complex optical routing systems.
Solution Approach 2:
The patent applies dimensionality change by transitioning from a simple planar light path to a three-dimensional optical path through the dielectric structures. The dielectric pillars or cavities create vertical and lateral light paths through total internal reflection, effectively increasing the optical path length in multiple dimensions simultaneously rather than simply extending the path in one direction.
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 sensitivity of the photodetector by ensuring that photons are reflected multiple times within the photosensitive material, increasing the likelihood of absorption and resulting in effective light detection.
Implementation Method 1
The integration of dielectric structures within the photodetector, which promote total internal reflection of light within the photosensitive material, increasing the path length of light
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.