Student Projects

Co‐supervisor: Fabio Bersano

Co‐supervisor: Sadegh Kamaei

Co‐supervisor: Ali Gilani

Co‐supervisor: Igor Stolichnov

Co‐supervisor: Ali Gilani

Project requirements: basic theoretical knowledge of cleanroom fabrication and biochemistry knowledge

Main tasks: Biosensor characterization

Starting date:  As soon as possible

Recommended type of project:  Master project or internship.

Work breakdown: 10% theory, 20% fabrication, 70% characterization.

Contact person:  Ali Gilani

Co‐supervisor: Nataliya Yakymets

Description:

Various new nonvolatile memory (NVM) technologies have emerged recently. Among them, ferroelectric memory devices are regarded as the promising candidates for edge computing architectures. Ferroelectric devices have been explored in NANOLAB and show behaviors that could be taken advantage of by using in embedded system architectures with low power consumption.

The proposed master thesis will focus on the exploration of the relationship that exists between retention, cycling and write energy. This trade-off has been identified in some NVM technologies but to the best of our knowledge, no real exploration from device characterization to architectural considerations have been done so far. We thereby propose to explore this track in a master thesis.

This master thesis proposes to characterize single devices that have been fabricated in NANOLAB  to study the link between programming energy, data retention and aging (life cycles).

Project requirements: 

• Good knowledge of device characterisation.
• Good analytical and modeling skills.
• Knowledge about NVM technologies, ferroelectric memory device
• knowledge and interest on electrical simulation and CMOS technologies. Good programming skills will be an advantage.
• Knowledge of SPICE.

Main tasks:

• A state-of-the-art analysis for ferroelectric memory devices and their use in architectural considerations.
• Characterization of the ferroelectric devices (1C and ferroelectric-gate MOS transistors) to identify and formalize the link between programming energy, retention and endurance.
• Development of a predictive model to explore how this memory devices could be embedded inside the memory architecture of a complete system. Bottom-up approach by first characterizing the energy consumed by the different operations in a realistic environment. Second by deriving a model that could be built on NVSim for e.g.

Recommended type of project:  Master thesis.

Contact person: Nataliya Yakymets

Co‐supervisor: Hung-wei Li

Overview

This semester-long project aims to investigate the properties and applications of ferroelectric materials through the lens of supercapacitor technology. Students will have the opportunity to delve into the fabrication and testing of various electrode designs, focusing on their effects when different polarizations are applied to ferroelectric materials. The project will utilize NiCuOx and Fe₂O₃ as active materials and tailored architectures for optimized performance.

Objectives

1. To fabricate various designs of electrodes using NiCuOx and Fe₂O₃ as active materials.
2. To test the effects of different polarizations on the ferroelectric material.
3. To understand the underlying principles of how ferroelectric materials work.

Methodology

Fabrication Phase

• Material Preparation: Students will deposit NiCuOx and Fe2O3 as active materials for the electrode in the cleanroom.
• Electrode Design: Multiple designs of electrodes will be fabricated, with these materials deposited on the Pt layer of the supercapacitor.

Testing Phase

• Polarization Experiments: A series of experiments will be conducted to apply different polarizations to the ferroelectric material.
• Electrochemical Experiments:  Conduct cyclic voltammetry, galvanostatic charge-discharge, and impedance spectroscopy tests, to estimate the performance of devices.

Expected Outcomes

• A deeper understanding of ferroelectric materials.
• A set of optimized electrode designs for ferroelectric supercapacitors.
• Insights into the effects of different polarizations on ferroelectric materials.

Starting date: As soon as possible 

Recommended type of project:  Semester project.

Work breakdown: 20% theory, 50% fabrication, 30% characterization.

Contact person: Hung-wei Li

Co‐supervisor: Vanessa Conti

Overview

VO2 is a phase change material able to pass from an insulating-monocline phase to a conductive-rutile one when reaching a critical carrier concentration, while HfO2 is a commonly used high-k dielectric that exhibits ferroelectricity under particular process conditions (doping, controlled annealing), when crystallizing in an orthorhombic phase. A successful integration of these two materials would help into the development of an efficient way to gate a VO2 transistor, leading to the possibility to realize devices for neuromorphic computing and memory applications.

The aim of this project is to study the structural and electrical properties of Si:HfO2 and VO2 once the former is deposited on top of the latter. Particularly, the student will have the task to study the possibility to anneal the stack using a flash-lamp annealing (FLA) tool, which thanks to its highly localized heat supply should be able to cause a minor number of damages to the underneath VO2 layer with respect to a conventional rapid-thermal process (RTP).

In order to reach the goal, Si:HfO2 and its metallic capping layer will be deposited (ALD, sputtering) on top of an already made VO2 thin film PLD deposited. The stack will be subsequently annealed in different thermal and ambient conditions. Structural characterization of the annealed stack will be done by means of several techniques (SEM, XRD, scanning probe microscopies) and the output will be correlated with the different annealing processes. Subsequently, different set of measurements (ex. CV, PUND, C-AFM, PFM) will be done on the samples with the desired structural properties in order to characterize the ferroelectric properties of the Si:HfO2 and the integrity of the VO2. To fabricate the electrical test structures, the samples will be processed in CMi cleanroom (metal deposition, laser direct writing, etching).

Possibly, different capping layers options could be explored as an alternative to the standard TiN layer.

Expected workload for the student:

• Initial literature review
• Fabrication of the capping layer – ferroelectric – VO2 stack (ALD, sputtering)
• Annealing of the stack (RTP, FLA)
• Structural characterization (mostly SEM, XRD, possibly AFM)
• Fabrication of capacitor structures on the stack (sputtering, MLA, wet etching / IBE)
• Electrical measurements (mostly with a parameter analyzer, possibly C-AFM and PFM)

Expected learning outcome:

• Basic understanding on the design of an experiment procedure
  • How to interpret and communicate the data
• Microfabrication skills in a real cleanroom environment
• Structural and electrical characterization experience
• General knowledge on ferroelectric and phase change materials

Requirements:

• Background in electrical engineering, material science, physics et similar
• General knowledge about semiconductor physics and devices, characterization methods
• Basic understanding of microfabrication processes
• Python/MATLAB/… for data analysis

Starting date: Spring 2024

Recommended type of project:  Master Thesis Project

Contact person: Vanessa Conti