UV Photodiode Structure Using Infrared Conversion and Reflection
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Solution Overview
Problem
Conventional silicon photodiodes exhibit a significantly low optical response to ultraviolet light, limiting their ability to effectively detect UV radiation.
Innovation Solution
Incorporating an infrared conversion layer and an infrared reflection layer on the photodiode, which converts ultraviolet light into infrared light, enhancing the light detection capability by allowing the infrared light to be more effectively absorbed and converted into an electric current, while the infrared reflection layer reflects escaped infrared light back into the photodiode for further conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional silicon photodiode structure is used, then the device is simple and easy to manufacture, but the optical response to ultraviolet light is extremely low
Solution Approach 1:
An infrared conversion layer is introduced as an intermediary between the ultraviolet light source and the silicon photodiode. This layer converts ultraviolet light into infrared light, which the silicon photodiode can detect with high efficiency. The intermediary transforms the mismatch between UV light and silicon detector response, enabling effective UV detection while maintaining simple silicon photodiode structure.
Solution Approach 2:
The patent changes the wavelength parameter of the light by using an infrared conversion layer that transforms ultraviolet light (high energy, short wavelength) into infrared light (lower energy, long wavelength). This parameter transformation allows the silicon photodiode to detect the converted infrared light, thereby achieving ultraviolet light detection capability.
2Measurement precision
If the infrared conversion layer is added to convert ultraviolet light to infrared light, then the optical response efficiency in UV band is improved, but the device structure becomes more complex
Solution Approach 1:
The infrared conversion layer serves multiple functions: it converts ultraviolet light to infrared light, acts as an optical interface between UV source and silicon detector, and can be integrated with existing photodiode structures. This multi-functionality justifies the added structural complexity by providing comprehensive solution to UV detection problem.
3Measurement precision
If the infrared reflection layer is added to reflect escaped infrared light back into the photodiode, then the light absorption efficiency is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The infrared reflection layer ensures continuous detection by reflecting infrared light that would otherwise escape back into the silicon photodiode. This creates a continuous detection cycle where photons that miss the first pass are given another opportunity to be detected, improving overall detection efficiency and signal strength.
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 ultraviolet light sensing-enhanced photodiode achieves a higher optical response efficiency in the UV band, comparable to the infrared band, by converting UV light into infrared light and utilizing reflective layers to increase light penetration and absorption, thereby improving UV detection capabilities.
Implementation Method 1
When the ultraviolet light strikes the infrared conversion layer, it is absorbed by the infrared conversion layer and subsequently re-emitted as the infrared light
Implementation Method 2
the infrared reflection layer is an infrared total reflection stacked layer that is made of multiple layers of high refractive index material dielectric films interlaced with low refractive index material dielectric films
Implementation Method 3
the first portion of the infrared light is propagated to the silicon photodiode and is transformed into an electric current by the silicon photodiode
Implementation Method 4
an ultraviolet light anti-reflection layer which is disposed the top layer of the ultraviolet light sensing-enhanced photodiode for forming destructive interference to a reflected light generated by the ultraviolet light incident
Data Source
AI summary
The present disclosure provides a structure of an ultraviolet light sensing-enhanced photodiode. The main structure of the photodiode includes a silicon photodiode and an infrared conversion layer formed on a surface that receives an ultraviolet light of the of the silicon photodiode. When the ultraviolet light irradiates on the ultraviolet light sensing-enhanced photodiode through the infrared conversion layer, the infrared conversion layer converts the ultraviolet light into an infrared light. The first portion of the infrared light is propagated to the silicon photodiode and then converted to a photoelectric current. The second portion of the infrared light is absorbed by the infrared conversion layer. An infrared reflection layer is also provided for reflecting the third portion of the infrared light that is originally escaped from the infrared reflection layer, and the third portion of the infrared light can be reflected into the silicon photodiode.