Avalanche Photo-Transistor Interim Doping Region
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Solution Overview
Problem
Existing optical transducers are inefficient and leaky, leading to loss of optical energy when converting light signals to electrical signals for processing.
Innovation Solution
An avalanche photo-transistor (APT) device with a three-terminal configuration, featuring an interim doping region between the detection and multiplication regions, allows for separate biasing and amplification of charge carriers, utilizing a heavily-doped p+ layer to reduce sensitivity to doping fluctuations and achieve avalanche breakdown at lower voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If existing optical transducers are used to convert light signals to electrical signals, then the conversion process occurs, but optical energy is lost due to inefficiency and leakage
Solution Approach 1:
The device is divided into three distinct regions: a detection region for absorbing light and generating charge carriers, an interim doping region for sweeping carriers, and a multiplication region for amplifying carriers. This segmentation allows each region to be optimized for its specific function, reducing energy loss and improving overall conversion efficiency
Solution Approach 2:
An interim doping region with high dopant concentration (≥10^18 cm^-3) is introduced between the detection region and multiplication region. This intermediary region acts as a carrier sweep zone that efficiently transports charge carriers from the detection region to the multiplication region, reducing carrier leakage and energy loss while maintaining reliable conversion
2Power
If high biasing voltages are applied to achieve avalanche breakdown and carrier multiplication, then signal amplification is achieved, but power consumption increases and device stability decreases
Solution Approach 1:
The interim doping region uses high dopant concentration (≥10^18 cm^-3) to modify the electrical characteristics of the device. This parameter change enables the multiplication region to achieve avalanche breakdown and carrier multiplication at lower biasing voltages, reducing power consumption while maintaining signal amplification capability
Solution Approach 2:
Different regions of the device have different doping concentrations optimized for their specific functions: the detection region has lower doping for efficient light absorption, the interim doping region has high doping (≥10^18 cm^-3) for carrier sweeping, and the multiplication region has graded doping for controlled avalanche breakdown. This local quality optimization allows low-voltage operation with effective signal amplification
3Use of energy by stationary object
If doping concentration is reduced to lower biasing voltages, then power consumption decreases, but sensitivity to doping fluctuations increases
Solution Approach 1:
The interim doping region uses high dopant concentration (≥10^18 cm^-3) to create a stable electrical field for carrier sweeping. This high doping level provides robust control over carrier transport, making the device less sensitive to doping fluctuations while enabling lower biasing voltages for the multiplication region, thus reducing power consumption
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 APT device achieves efficient conversion and amplification of optical signals with reduced biasing voltages, improving power budget and stability, enabling its use in consumer applications with commercially available power supplies and minimizing premature punch-through and dark current issues.
Implementation Method 1
a detection region configured to absorb light incident on a first surface of the detection region and generate one or more charge carriers in response to absorbing the incident light
Implementation Method 2
a multiplication region configured to receive the one or more charge carriers flowing from the interim doping region and generate one or more additional charge carriers in response to receiving the one or more charge carriers
Data Source
AI summary
Methods and devices for an avalanche photo-transistor. In one aspect, an avalanche photo-transistor includes a detection region configured to absorb light incident on a first surface of the detection region and generate one or more charge carriers in response, a first terminal in electrical contact with the detection region and configured to bias the detection region, an interim doping region, a second terminal in electrical contact with the interim doping region and configured to bias the interim doping region, a multiplication region configured to receive the one or more charge carriers flowing from the interim doping region and generate one or more additional charge carriers in response, a third terminal in electrical contact with the multiplication region and configured to bias the multiplication region, wherein the interim doping region is located in between the detection region and the multiplication region.