Diploma Thesis / Project Work / Bachelor- and Master-Thesis

Screening of different electrodes for resistive random access memory (RRAM) devices based on HfO₂ switching material (*)

• Fabrication of metal-insulator-metal (MIM) devices with various electrode configurations
• Electrical characterization of the MIM structures

Correlation of HfO₂ atomic layer deposition parameters with switching properties of resistive random access memory devices (*)

• Fabrication of HfO₂ based metal-insulator-metal (MIM) devices with extensive parameter variations during ALD of HfO₂
• Structural characterization of HfO₂ and electrical characterization of the MIM structures

Process development for the fabrication of Indium Gallium Zinc Oxide (IGZO) based devices and electrical characterisation

• thin film transistors
• memristors

Reliability of IGZO-based devices:

• temperature and time-dependent stress measurement on thin film transistors
• retention and endurance measurements on memristor devices

Electrochemical investigation of Ru surfaces by underpotential deposition of copper ions

• Despite being a noble metal ruthenium has a high affinity towards oxygen. So, sorption of oxygen-species, so-called “surficial oxides”, is possible. The extension of coverage can be quantified by underpotential deposition of copper ions (Cu-UPD) resulting in sub-monomolecular coverage.

• The Cu-UPD investigation can be combined with other electrochemical methods or with spectroscopic studies.

Electrolytic hydrogen incorporation into silicon single crystals

• Hydrogen (H₂) can be incorporated into silicon single crystals by electrochemical means. According to literature one opportunity is cyclic voltammetry (CV) using silicon single crystal (Si wafer specimen) as the cathode, platinum as the counter and hydrogen electrode as the reference electrode. These CV experiments are carried out in fluoric acid solutions in PTFE vessels. The amount of incorporation is obviously dependent on the type of Si crystallization as well as on the level and type of doping and can be measured by physical methods like Raman scattering.

Development and analysis of complex memristors on multilayer material stacks. The work includes:

• deposition of the bottom electrode and the switching oxide layer by Atomic Layer Deposition (ALD)
• deposition of the upper electrode by physical vapor deposition (PVD) using a shadow mask
• Etching of the oxide layer using Reactive Ion Etching (RIE)
• Electrical measurements to analyze the I-V characteristics of the memristor and evaluate the hysteresis loops