Student projects

General information

A lump sum of CHF 600.- for transportation expenses’ support will be given to each student doing his/her semester project in AQUA in Neuchâtel.

A lump sum of CHF 1600.- for transportation expenses’ support will be given to each student doing his/her Master project in AQUA in Neuchâtel.

Doing a part of the project in Lausanne can be discussed. The lump sum would then be adapted proportionally to the number of trips to Neuchâtel.

No refund of effective fees will be provided. We advise students coming to do a project in Neuchâtel to buy a half-fare subscription.

 

Master projects

Characterization and Analysis of Novel Photodetector Devices

General Information

Laboratory: Advanced Quantum Architecture Laboratory (AQUA)

Partners: EPFL

Supervisor: Francesco Gramuglia, Prof. Edoardo Charbon, Claudio Bruschini, PhD

Location: Microcity, Neuchâtel

Starting date: ASAP

Description

The objective of this project is to analyze the functionality and characterize novel single photon detectors based on SPADs, developed in our lab.

The activity will include optical and electrical setup implementation and devices characterization as well as firmware and software implementation.

This project can be adapted as a semester, master project or full-time internship.

For additional details, please contact us by email.

Tasks:

  • Analyze the basic performance of the devices (sensitivity and timing)
  • Firmware implementation for system readout and data analysis
  • Software implementation for data post processing (C++, Python or Matlab)
  • Deep characterization of the device performance at system level
  • Application related measurements

Expected Candidate Achievements:

  • Understanding of SPAD/SPAD arrays behavior and characteristics
  • Knowledge on how to use the setups for SPAD-based devices characterization
    • Optical setups (pulsed Laser setups, continuous light setups)
    • Electrical instruments (Supplies, Oscilloscopes, Climate chamber, etc.)
    • Embedded systems (FPGA boards, custom PCB systems)
    • Radioactive sources
  • Understanding of some of the most common applications

Candidate requirement:

  • Basic knowledge of HDL (VHDL or Verilog)
  • Basic Knowledge of programming languages (such as C++, Python or Matlab) is preferred
  • Some basics of Electronics

Contact: [email protected]

Testing of a 512×1 Event-Driven Linear SPAD Array

The objective of this project is to characterize and test the 512×1 linear SPAD array. The detector and system performance parameters to be measured are dark count rate, photon detection probability, dead time and maximum excess bias. The first task towards this goal is to develop a camera module based on a commercial FPGA board. The part to be designed is a sensor board with the chip mounted on it, which is compatible with the FPGA board. The second task is to develop the readout block of the sensor, starting from existing firmware. The lack of on-chip electronics resulting from the reconfigurable structure requires the implementation of readout modules on an FPGA, using VHDL. The firmware needs to send the control signals to the chip for the desired operational settings and collect the detected photons with their address in the array and timing delay from the laser pulse, in an event driven configuration. Finally, the information needs to be stored in the on board DDR3 RAM blocks and transferred to the PC via USB 3.0. Further specifications of the control and readout modules will be finalized depending on the details of the target application.

Details (PDF)

Contact: [email protected]

Camera Module Development for a Large Format Time-Resolved SPAD Image Sensor

The objective of this project is to develop a camera module that can perform FLIM-FRET analysis based on the existing 512×512 SPAD array. In addition to the currently available integrated SPAD sensor and two commercial FPGA integration boards, the required parts for this module are a custom designed sensor board with chip-on-board technology and a firmware written in VHDL. The firmware must control the camera operation signals from the FPGA, store the acquired data in DDR3 RAM blocks on the integration board, recover the fluorescence lifetimes in the FPGA and finally transfer the processed data to the PC via USB 3.0. The entire process must be performed in real time, where the overall speed is determined by the maximum readout speed of the sensor, 100 kfps for 1-bit images. The detailed description of the FLIM-FRET algorithm, standard MATLAB functions of the FPGA board and a test module for the half array 512×256 will be available for reference.

Details (PDF)

Contacts: [email protected]

Fabrication of InGaAs/InP based single photon avalanche detectors optimized for high efficiency at near infrared

The goal of the project is to demonstrate efficiency improvement at wavelengths below 900 nm by comparing the single photon efficiency spectrum of two InGaAs/InP SPADs with and without substrate. For this purpose student should fabricate these devices in CMi (Center of Micronanotechnology) by following various photolithography, etching, metallization and thinning processes. Following the fabrication, devices should be placed on a PCB and characterized for their photon detection efficiency. The student will have a chance to experience/perform all of the fabrication process of a single photon avalanche detector from scratch and set up an experiment to analyze the performance of the detector.

This project can be adapted as a semester or Master project.

Details (PDF)

Contact: [email protected]

3D device modelling of miniaturized SPADs

To construct compact and cost-effective multi-megapixel SPAD cameras it is crucial to investigate further miniaturization of the SPAD pixels toward 3-7 um, which can be arrayed in small sensor formats. However, reducing the active area dimensions to a few micrometers may lead to a dramatic decrease of photon detection probability (PDP) and increase the risk of premature edge breakdown due to three dimensional effects in the electric field distribution.

The objective of this work is to construct a 3D device simulation model with TCAD and clarify the impact of pixel miniaturization on basic SPAD performance parameters, e.g. PDP and dark count rate (DCR).

This project can be adapted as a semester of master project.

Details (PDF)

Contact: [email protected]

 

Semester projects

Fabrication of InGaAs/InP based single photon avalanche detectors optimized for high efficiency at near infrared

The goal of the project is to demonstrate efficiency improvement at wavelengths below 900 nm by comparing the single photon efficiency spectrum of two InGaAs/InP SPADs with and without substrate. For this purpose student should fabricate these devices in CMi (Center of Micronanotechnology) by following various photolithography, etching, metallization and thinning processes. Following the fabrication, devices should be placed on a PCB and characterized for their photon detection efficiency. The student will have a chance to experience/perform all of the fabrication process of a single photon avalanche detector from scratch and set up an experiment to analyze the performance of the detector.

This project can be adapted as a semester or Master project.

Details (PDF)

Contact: [email protected]

Modelling and analysis of Cherenkov detection for Positron Emission Tomography using Single-Photon-Avalanche Diodes

Positron Emission Tomography (PET) is a non-invasive medical imaging technique used for 3D observation of metabolic processes in the body, heavily used in clinical oncollogy. Since the technique uses time-of-flight information in order to reconstruct the image of the area of interest, a fast system is required in order to enhance the resolution of the 3D image. Despite the efforts in trying to speed up the electronics of the system, it is not the only bottleneck, since the jitter of the system is present in many forms (also in the scintillating crystal). Cherenkov luminescence is a prompt-photon generation mechanism which improves timing performance. This effect arises from the interaction between a charged particle travelling faster than the phase velocity of light in a dielectric medium. The number of detected Cherenkov photons is limited by the photon detection efficiency of the photodetector. Moreover, the detector’s noise such as crosstalk, dark count rate, afterpulsing and single-photon timing resolution have a great influence on the detection of Cherenkov photons.

Details (PDF)

Contact: [email protected]

Characterization and analysis of the first fully integrated A-SiPM with on-chip time conversion: Blumino sensor

The objective of this project is to characterize and analyse the performance of the first fully integrated analog silicon photomultiplier used in Blumino, a sensor designed for positron-emission-tomography (PET). The system comprises an A-SiPM developed by On-Semiconductor, with excellent photon detection efficiency (PDE) at 420nm (48%) designed for PET, an integrated time-to-digital converter (TDC) and comparator. This work is divided in three different areas: electrical, optical and radiation characterizations. The system is optically characterized in terms of single-photon timing resolution (SPTR), photo detection efficiency  (PDE), dark count rate (DCR) and crosstalk. Coincidence resolving time (CRT) measurements are performed in order to determine the system performance PET. One of the major goals is to investigate the impact of integrating CMOS circuits along with the A-SiPM monolithically. We compare the obtained results with previous characterisations in order to detect any possible performance degradations due to the integration.

Details (PDF)

Contact: [email protected]

3D device modelling of miniaturized SPADs

To construct compact and cost-effective multi-megapixel SPAD cameras it is crucial to investigate further miniaturization of the SPAD pixels toward 3-7 um, which can be arrayed in small sensor formats. However, reducing the active area dimensions to a few micrometers may lead to a dramatic decrease of photon detection probability (PDP) and increase the risk of premature edge breakdown due to three dimensional effects in the electric field distribution.

The objective of this work is to construct a 3D device simulation model with TCAD and clarify the impact of pixel miniaturization on basic SPAD performance parameters, e.g. PDP and dark count rate (DCR).

This project can be adapted as a semester of master project.

Details (PDF)

Contact: [email protected]

Fabrication of high aspect ratio Though-Silicon Vias

The project is going to focus on the fabrication of high aspect ratio Through-Silicon Vias. The project will consist in three main phases.
1.       Preparation [first month]. In the first phase, the student will design the mask for the photolithography of the TSVs and will get all the trainings required by the CMi staff in order to be independent in the fabrication process. During this phase the student will learn how to design .gds files in an automatic way using the python library gdsCAD. Then, the student will help fabricate the photolithography mask she will use for the TSV design.
2.       Analysis [core of the project]. In the second phase, the student will learn how to fabricate the TSVs following two different process flows, and will show and analyze, by means of SEM images, the TSV quality difference and will extrapolate guidelines for the design process. During the fabrication, the student will sweep some parameters to assess their influence in the fabrication process:
a.       Materials used for the seed and adhesion layers deposition.
b.       TSV quality dependence with respect to the aspect ratio.
c.        TSV pitch, to assess if there is any proximity effect playing a role in the fab process and at what point it becomes relevant.
3.       Optimization [last month]. In the third and final phase, the student will, with the acquired knowledge from phase two, design and fabricate a wafer with the highest aspect ratio he/she expects to get.

Details (PDF)

Contact: [email protected]

Investigation of superconducting nanowire performance on different substrates

The project is going to focus on the fabrication and testing of impedance mismatching superconducting nanowire resonators made of NbTiN on a different range of substrates (SiO2, TiO2, Si3N4, Al2O3, AlN, AlN-on-Sapphire and MgO). The student is going to perform an analysis similar to what has been shown by Zhang and You [7], but focusing on the achievable depairing current fraction [8] of the thin films grown on different substrates. The student will develop skills in fabrication processes, cryogenics, data acquisition and data analysis.

Details (PDF)

Contact: [email protected]