Light Receiving Pixel Structure for Edge Breakdown Suppression
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Solution Overview
Problem
Miniaturization of pixels in distance measuring sensors leads to unintended edge breakdown due to reduced distance between cathode and anode electrodes.
Innovation Solution
Incorporating a third semiconductor region of the same conductivity type as the first semiconductor region, which is not connected to any wiring outside the first semiconductor region, to relax the electric field and prevent edge breakdown, while maintaining the power supply voltage to the first semiconductor region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the pixel size is reduced for miniaturization, then the integration density is improved, but unintended edge breakdown occurs due to reduced distance between cathode and anode electrodes
Solution Approach 1:
A third semiconductor region of the first conductivity type is introduced as an intermediary structure between the cathode electrode and the first semiconductor region. This intermediate region relaxes the electric field at the edges of the cathode electrode, preventing unintended edge breakdown while allowing the pixel to maintain a compact size. The third semiconductor region acts as a buffer that mediates the electric field distribution, solving the contradiction between miniaturization and reliability.
2Length of stationary object
If the distance between cathode electrode and first semiconductor region is reduced, then the pixel area is decreased, but the electric field concentration increases causing edge breakdown
Solution Approach 1:
The third semiconductor region is selectively positioned at specific locations where edge breakdown is most likely to occur, such as at the edges or corners of the cathode electrode. This local modification relaxes the electric field concentration precisely where needed, without affecting the overall compact design. By applying the solution locally rather than globally, the patent maintains small pixel dimensions while preventing edge breakdown at critical points.
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 configuration effectively reduces unintended edge breakdowns during pixel miniaturization, enhancing the accuracy and reliability of distance measurements by maintaining a wider distance between the anode and cathode electrodes and preventing dark current generation.
Implementation Method 1
a third semiconductor region of the first conductivity type that is not connected to any wiring outside the first semiconductor region... to relax the electric field and prevent edge breakdown
Implementation Method 2
avalanche amplification occurs when one photon enters a PN junction region of a high electric field in a state where a voltage (hereinafter referred to as Excess Bias) larger than a breakdown voltage is applied
Implementation Method 3
one photon enters a PN junction region... By detecting the timing at which the current instantaneously flows at that time, the distance can be measured
Data Source
AI summary
The present technology relates to a light receiving element, a distance measuring system, and an electronic device capable of reducing unintended edge breakdown in a case where a pixel is miniaturized. A light receiving element includes a pixel that includes a PN junction region in which a first semiconductor region of a first conductivity type and a second semiconductor region of a second conductivity type opposite to the first conductivity type are joined, and a third semiconductor region of the first conductivity type that is not connected to any wiring outside the first semiconductor region near a first surface of a substrate on which a wiring that supplies a predetermined power supply voltage to the first semiconductor region is formed. The present technology can be applied to, for example, a distance measuring sensor that receives reflected light and measures a distance, and the like.