Light Detecting Device with Alternating Doping for High AC Bandwidth
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Solution Overview
Problem
Existing photodiodes face limitations in terms of quantum efficiency, operational wavelength, and sensitivity, which affect their overall performance in converting optical signals into electrical currents.
Innovation Solution
A light detecting device with alternating n-doped and p-doped regions within a silicon layer and a light detecting layer, allowing for increased photocurrent generation and reduced parasitic capacitance, thereby enhancing the AC bandwidth and mitigating optical propagation delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photodiode structures are used, then manufacturing is simpler, but quantum efficiency and sensitivity are limited
Solution Approach 1:
The photodiode structure is segmented into multiple alternating n-doped and p-doped regions within the light detecting layer, creating multiple photocurrent generation zones. This segmentation increases the total photocurrent generation area and improves quantum efficiency while maintaining a manageable device structure through systematic repetition of doped regions.
Solution Approach 2:
Different regions of the light detecting layer are selectively doped with alternating n-type and p-type dopants to create localized areas with different electrical properties. This local quality variation enables multiple photocurrent generation sites with optimized carrier separation, improving overall sensitivity without requiring complete structural redesign.
2Reliability
If photodiode size is increased to improve sensitivity, then detection capability improves, but parasitic capacitance increases
Solution Approach 1:
The photodiode is divided into multiple small alternating n-doped and p-doped regions instead of using a single large junction. This segmentation increases the total detection area and sensitivity while keeping each individual junction small, thereby reducing the parasitic capacitance associated with each junction and the overall device.
Solution Approach 2:
The patent transitions from a conventional single-plane junction structure to a multi-dimensional alternating doped region structure within the light detecting layer. This dimensional reorganization allows the photodiode to achieve high sensitivity through increased effective area while maintaining low parasitic capacitance through the distributed nature of the alternating doped regions.
3Speed
If AC bandwidth is increased to improve high-speed performance, then data transmission speed improves, but optical propagation delays become more significant
Solution Approach 1:
The light detecting layer is segmented into multiple alternating doped regions that generate photocurrents simultaneously across different locations. This segmentation enables parallel photocurrent generation, increasing the effective AC bandwidth by processing optical signals across multiple zones concurrently, thereby compensating for optical propagation delays through spatial distribution.
Solution Approach 2:
The alternating n-doped and p-doped regions create continuous photocurrent generation throughout the light detecting layer, ensuring that optical signal detection is ongoing across the entire structure. This continuity of useful action maintains high AC bandwidth by eliminating dead zones and ensuring constant carrier generation and separation across all regions.
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 device achieves higher photocurrent generation rates and broader AC bandwidth, up to several hundred GHz, while minimizing parasitic capacitance and optical propagation losses.
Implementation Method 1
Photodiodes are used in converting received photons into electrical currents
Data Source
AI summary
The present disclosure provides a method of manufacturing a light detecting device. The light detecting devices includes an insulating layer, a silicon layer, a light detecting layer, N first doped regions and M second doped regions. The silicon layer is disposed over the insulating layer. The light detecting layer is disposed over the silicon layer and extends within at least a portion of the silicon layer. The first doped regions have a first dopant type and are disposed within the light detecting layer. The second doped regions have a second dopant type and are disposed within the light detecting layer. The first doped regions and the second doped regions are alternatingly arranged. M and N are integers equal to or greater than 2.