SPAD Quench Element Integration in Semiconductor Well
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing photoelectric conversion apparatuses with single photon avalanche diodes (SPADs) lack effective integration of quench elements and diodes on the same semiconductor substrate, with prior studies failing to optimize the layout of these components.
Innovation Solution
A photoelectric conversion apparatus is designed with a first semiconductor substrate containing both avalanche multiplication-type diodes and transistors forming quench elements, where the transistors are disposed between the diodes in a planar view and share a common semiconductor well region, facilitating high integration and efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If quench elements and diodes are integrated on the same semiconductor substrate, then device integration is improved, but layout optimization and element isolation become problematic
Solution Approach 1:
The patent merges the quench element and diode into a single integrated pixel structure on the same semiconductor substrate. The quench element is positioned adjacent to the diode with shared diffusion regions, eliminating the need for separate substrates and reducing overall device complexity while maintaining functional independence through proper electrical isolation.
Solution Approach 2:
The patent transitions from planar layout to three-dimensional vertical integration by stacking the quench element and diode in different vertical layers. This dimensional change allows both components to coexist on the same substrate without lateral interference, solving the layout optimization problem by utilizing the vertical dimension for component placement.
2Device complexity
If element isolation regions are reduced for higher integration, then manufacturing precision requirements increase
Solution Approach 1:
The patent implements nested diffusion regions where the quench element's diffusion regions are partially contained within or adjacent to the diode's diffusion regions. This nesting approach minimizes the required isolation regions while maintaining proper electrical separation, thereby reducing manufacturing precision requirements compared to fully separate layouts.
Solution Approach 2:
The patent applies different isolation strategies to different regions of the device. Critical isolation is maintained only where electrical interference occurs, while non-critical regions use minimal isolation. This localized approach to quality control reduces overall isolation region requirements without compromising device performance.
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 enhances the integration of diodes and reduces element isolation regions, enabling improved performance and efficiency in photon detection and signal processing within the photoelectric conversion apparatus.
Implementation Method 1
A reverse bias voltage equal to or higher than a breakdown voltage is applied to the diode, and the current is multiplied due to the avalanche multiplication
Implementation Method 2
a single photon avalanche diode (SPAD)... detecting an avalanche current that has occurred due to entry of a single photon
Data Source
AI summary
A photoelectric conversion apparatus includes a first diode which is an avalanche multiplication-type and a second diode which is an avalanche multiplication-type formed within a semiconductor substrate, a first transistor forming a first quench element, and a second transistor forming a second quench element. The first transistor and the second transistor are disposed between the first diode and the second diode in a planar view. The first transistor and the second transistor are disposed in a common semiconductor well region formed within the semiconductor substrate.