Single-Photon Detector Scanning for PICA Noise Reduction
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Solution Overview
Problem
Current imaging photodetectors for Picosecond Imaging for Circuit Analysis (PICA) face challenges such as high noise, hot-spots, non-uniformity, and high time jitter, limiting their sensitivity and effectiveness, especially in the Near-Infrared (NIR) region, which hinders the ability to accurately measure emissions from modern CMOS devices.
Innovation Solution
The use of high-performance single pixel photodetectors like Superconducting Single Photon Detector (SSPD) and InGaAs Single Photon Avalanche Diode (SPAD) in a Scanning Time-Resolved Emission (S-TRE) system, which focuses on precise photon arrival time measurement and combines with optical scanning to generate pseudo images of device under test (DUT), enabling improved imaging capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional imaging photodetectors are used for PICA measurements, then imaging capability is provided, but noise, hot-spots, non-uniformity, and high time jitter occur
Solution Approach 1:
The imaging function is segmented from the photodetector by using a scanning system to sequentially visit different spatial locations. A single high-performance photodetector (SSPD or SPAD) performs timing measurements at each location, and the scanning system reconstructs the full image. This separates the imaging function across space and time, allowing the photodetector to be optimized for timing without compromising spatial coverage.
Solution Approach 2:
The patent transitions from a 2D array of photodetectors to a 1D single-point photodetector combined with a scanning mechanism. The imaging capability is maintained by adding the temporal dimension through scanning, where each pixel is visited sequentially and its emission characteristics are measured over time. This dimensional transformation allows optimization of the photodetector for single-point timing precision.
2Measurement precision
If single pixel photodetectors with low noise and low jitter are manufactured, then measurement precision is improved, but manufacturing complexity increases and yield decreases
Solution Approach 1:
The patent extracts the imaging function from the photodetector itself and places it in the scanning system. Instead of manufacturing complex imaging photodetectors with integrated imaging capabilities, the system uses a simple single-point photodetector and achieves imaging through mechanical or optical scanning. This extraction simplifies the photodetector manufacturing while maintaining imaging capability through system-level coordination.
3Measurement precision
If photodetectors with high sensitivity in NIR region are used, then detection capability is improved, but acquisition time for light pulses increases
Solution Approach 1:
The scanning system continuously moves through the field of view, and the photodetector continuously measures photon arrival times at each location. By maintaining continuous scanning and measurement operations, the system efficiently collects data across the entire imaging area without significant idle time, optimizing the acquisition process while using high-sensitivity photodetectors.
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 approach significantly reduces acquisition time for light pulses from n-FETs, allows observation of weaker p-FET emissions, and enhances the capability to measure signal pulse width, duty cycle, and delays between signals with different phases, regaining imaging capability for PICA while optimizing single pixel detector performance.
Implementation Method 1
timing photodetector (42) capable of precisely measuring the arrival time of single-photon
Implementation Method 2
Superconducting Single Photon Detector (SSPD)
Implementation Method 3
InGaAs Single Photon Avalanche Diode (SPAD)
Implementation Method 4
InGaAs Single Photon Avalanche Diode (SPAD)
Implementation Method 5
scanning system (20) to focus spontaneous emissions from different areas of a device under test (DUT) onto a timing photodetector (42)
Data Source
AI summary
A Scanning Time-Resolved Emission (S-TRE) microscope or system includes an optical system configured to collect light from emissions of light generated by a device under test (DUT). A scanning system is configured to permit the emissions of light to be collected from positions across the DUT in accordance with a scan pattern. A timing photodetector is configured to detect a single photon or photons of the emissions of light from the particular positions across the DUT such that the emissions of light are correlated to the positions to create a time-dependent map of the emissions of light across the DUT. The scanning system is configured to updated the time-dependent map of the emissions based on a transformation of an underlying time-resolved waveform at certain intervals and corresponding to at least one location and generating a pseudo image of the DUT.