Stacked PIN Photodiode Regions for Lower Parasitic Capacitance
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Solution Overview
Problem
Detection devices using PIN photodiodes face a trade-off between increasing sensing area for improved detection sensitivity and the resulting increase in parasitic capacitance, which reduces sensitivity.
Innovation Solution
A detection device design featuring photodiodes with a stacked structure of p-type, i-type, and n-type semiconductor layers, where adjacent first regions are coupled by the p-type semiconductor layer, reducing parasitic capacitance while maintaining detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensing area of the PIN photodiode is increased to improve detection sensitivity, then the photocurrent increases, but the parasitic capacitance increases which reduces detection sensitivity
Solution Approach 1:
The photodiode sensing area is divided into multiple first regions arranged in a matrix pattern, with each region having a stacked structure of p-type, i-type, and n-type semiconductor layers. This segmentation allows the total sensing area to be increased while managing parasitic capacitance through the specific stacking configuration and coupling method of adjacent regions
Solution Approach 2:
Adjacent first regions are coupled together by the p-type semiconductor layer, merging multiple segmented regions into a unified sensing structure. This coupling maintains electrical connectivity across the expanded sensing area while the stacked configuration manages parasitic capacitance effects
Solution Approach 3:
The photodiode structure transitions from a planar configuration to a three-dimensional stacked structure with p-type, i-type, and n-type semiconductor layers vertically arranged. This dimensional change allows increased sensing area in the horizontal plane while managing capacitance through the vertical stacking configuration
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 solution enhances detection sensitivity by minimizing parasitic capacitance without compromising the sensing area, enabling effective detection of fingerprints and living body information.
Implementation Method 1
a detection device includes a substrate and a plurality of photodiodes arranged on the substrate. Each of the photodiodes comprises a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer stacked on the substrate
Data Source
AI summary
According to an aspect, a detection device includes a substrate and a plurality of photodiodes arranged on the substrate. Each of the photodiodes comprises a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer stacked on the substrate. Each of the photodiodes includes a plurality of first regions in each of which the p-type semiconductor layer, the i-type semiconductor layer, and the n-type semiconductor layer are stacked so as to be directly in contact with one another, and a second region in which at least the p-type semiconductor layer and the i-type semiconductor layer are stacked so as to be separate from each other. Adjacent first regions included in the plurality of first regions are coupled together by at least the p-type semiconductor layer.