SPAD Pixel Array Segmentation for Temperature-Dependent PDE
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Single photon avalanche photodiodes (SPADs) face challenges in maintaining high photon detection efficiency (PDE) across varying temperatures, as the breakdown voltage is temperature-dependent, leading to reduced avalanche probability at high temperatures and difficulty in reading electric charges at low temperatures.
Innovation Solution
A light-receiving device with a pixel array comprising multiple types of light-receiving elements, each optimized for specific temperature regions with high PDE. These elements are designed to partially overlap in their temperature regions, allowing for the use of appropriate elements at low and high temperatures to maintain high PDE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single type of SPAD is used, then the device structure is simple, but the photon detection efficiency degrades at temperatures outside a specific range
Solution Approach 1:
The pixel array is divided into multiple regions, with each region containing light-receiving elements optimized for specific temperature ranges. This segmentation allows different elements to operate optimally at different temperatures, resolving the contradiction between simple structure and reliable performance across temperature variations.
Solution Approach 2:
Different regions of the pixel array are assigned different characteristics - some regions have light-receiving elements optimized for low temperatures while others are optimized for high temperatures. This local differentiation ensures high photon detection efficiency across the entire temperature range without requiring a completely redesigned device structure.
2Reliability
If the bias voltage is increased to maintain avalanche probability at high temperatures, then the photon detection efficiency improves at high temperatures, but the breakdown voltage temperature dependence causes difficulty in reading electric charges at low temperatures
Solution Approach 1:
The device is segmented into multiple temperature regions, each with light-receiving elements designed for optimal operation at specific temperatures. This allows the system to maintain appropriate bias voltages for each region without causing breakdown issues at low temperatures or reduced avalanche probability at high temperatures.
Solution Approach 2:
The breakdown voltage characteristics are modified through changes in the multiplying region structure (such as impurity concentration and region thickness) in different temperature regions. This allows each region to operate with optimal bias voltage for its temperature range, resolving the contradiction between avalanche probability and charge reading ease.
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 effectively expands the temperature range where high photon detection efficiency is ensured, suppressing degradation in PDE at both low and high temperatures, and simplifies manufacturing processes by allowing different processes for different types of APDs.
Implementation Method 1
a light-receiving device with a pixel array comprising multiple types of light-receiving elements, each optimized for specific temperature regions with high PDE
Implementation Method 2
The SPAD is a device that is able to detect one photon at each pixel by multiplying a carrier generated by photoelectric conversion in a high electric field PN-junction region provided in each pixel
Data Source
AI summary
A light-receiving device according to an embodiment of the present disclosure includes a pixel array including light-receiving elements provided in respective pixels. The light-receiving elements each include a high electric field region and a photoelectric conversion region. A plurality of the light-receiving elements provided in the respective pixels includes a plurality of types of elements that have temperature regions having high photon detection efficiency (PDE). The temperature regions are different from each other and partially overlap each other.