Microchannel Avalanche Photodiode Segmentation for Dark Current Reduction
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Solution Overview
Problem
Existing semiconductor avalanche photodiodes face issues with low quantum output in the visible and ultraviolet spectrum due to poor transparency and high dark current, leading to reduced sensitivity and uncontrollable micro-sparkovers at the p-n junction interface, limiting the avalanche process's amplification factor.
Innovation Solution
The device incorporates a matrix of separate solid-state areas with enhanced conductivity surrounded by semiconductor material of the same type, located between two additional semiconductor layers with higher conductivity, creating potential micro-holes for improved photoelectron amplification and self-extinguishing avalanche processes, thereby reducing electric field and increasing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If semiconductor areas are located immediately on the p-n junction interface to create separate avalanche areas, then signal amplification is achieved, but uncontrollable local micro-sparkovers occur and current limitation is lost
Solution Approach 1:
The device segments the avalanche process into independent micro-channels by introducing insulating layers between semiconductor areas. Each area with enhanced conductivity is separated by insulating material, creating isolated avalanche regions that prevent cross-contamination and uncontrollable micro-sparkovers while maintaining signal amplification capability
Solution Approach 2:
Insulating layers are introduced as intermediary elements between the semiconductor areas and the p-n junction interface. These insulating layers act as mediators that enable current localization within each semiconductor area while preventing direct electrical connection that would cause micro-sparkovers, thus achieving both amplification and reliability
2Power
If buffer layer and highly doped semiconductor areas are used for avalanche amplification, then signal amplification is achieved, but quantum output decreases due to poor transparency
Solution Approach 1:
The invention moves the avalanche amplification process from a planar interface configuration to a three-dimensional structure where semiconductor areas with enhanced conductivity are embedded within insulating layers at a distance from the p-n junction interface. This spatial reconfiguration allows photons to pass through with minimal absorption while still enabling effective avalanche amplification in the separated semiconductor regions
Solution Approach 2:
Insulating layers serve as intermediaries that separate the photosensitive region from the avalanche amplification regions. This separation allows the photosensitive layer to maintain high transparency for detecting photons while the semiconductor areas embedded in insulating layers provide the necessary avalanche gain, resolving the contradiction between transparency and amplification
3Power
If device voltage is increased to attain high avalanche process level, then amplification factor increases, but micro-sparkovers occur at areas with decreased sparkover potential
Solution Approach 1:
The device segments the high-voltage avalanche process into isolated micro-channels separated by insulating layers. Each semiconductor area operates as an independent high-field region where avalanche multiplication occurs, while the insulating barriers prevent lateral spread and micro-sparkovers, enabling high amplification factors without harmful discharge effects
Solution Approach 2:
The invention converts the potential harmful effect of high electric fields causing micro-sparkovers into a beneficial localized avalanche process. By confining the high-field regions within insulating layers, the design allows operation at high voltages necessary for strong amplification while the insulating barriers transform what would be harmful discharge into controlled, localized multiplication channels
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 stability and amplitude of the photodiode's response, improving sensitivity and reducing dark current, allowing for efficient amplification of photoelectrons in independent channels with self-extinguishing avalanche processes.
Implementation Method 1
Avalanche amplification of the photoelectrons takes place on the boundaries between the substrate and the semiconductor areas
Implementation Method 2
registration of super feeble light pulses, including up to individual photons
Data Source
AI summary
The invention is directed to an avalanche photodiode containing a substrate and semiconductor layers with various electro-physical properties having common interfaces both between themselves and with the substrate. The avalanche photodiode may be characterized by the presence in the device of at least one matrix consisting of separate solid-state areas with enhanced conductivity surrounded by semiconductor material with the same type of conductivity. The solid-state areas are located between two additional semiconductor layers, which have higher conductivity in comparison to the semiconductor layers with which they have common interfaces. The solid-state areas are generally made of the same material as the semiconductor layers surrounding them but with conductivity type that is opposite with respect to them. The solid-state areas may be made of a semiconductor with a narrow forbidden zone with respect to the semiconductor layers with which they have common interfaces.