PhD - Leuven | More than two weeks ago
There is always an ever-growing demand for fast and reliable devices in computation and memory technology. This acts as a driving force towards continuous exploration and study of complex materials to achieve good device specifications such as high scalability, low power consumption, non-volatility and high endurance. A good example is the extensive research being carried out now on phase change memories (PCM), resistive random access memories (Re-RAM) and ovonic threshold selectors (OTS) to replace the conventional Static-RAM (SRAM), whose drawbacks include poor scalability from the use of multiple transistors, volatility and high operational power consumption. These advanced memories and selectors employ the use of complex ‘novel metal alloys’ such as chalcogenides (GeSbTe, SiGeAsTe, SiGeAsSe) and metal oxides like InGaZnO. They portray intrinsic electronic properties which make them optimal for advanced class of PCMs, Re-RAMs and OTS.
Current challenges & research description
A key challenge in implementing these aforementioned metal alloys and metal oxides into an actual integration scheme is their patterning at nano-scale level without damaging or interfering with their intrinsic properties. Typically, dry reactive ion/chemical etch techniques are desired to attain high scalability. This means the etch gas (/etchant) will chemically react with the metal system under consideration and generate volatile by-products to leave behind features of different dimensions and shapes (defined by the lithography masks being used). And, herein lies the importance to study and understand the interaction of an ‘etch’ plasma with the metal systems. A chemical reaction between the etchant and the metal system is never a binary process, and is prone to generate some undesirable collateral effects. For instance, the metal system under consideration may get doped with the etchant during the etch process or the metal surface may be chemically modified post the patterning step. There can also be possibilities of void formation and defect generation in the metal films due to the use of a certain type of chemical etch technique and plasma parameters (temperature, precursor of the etchant). It is therefore extremely critical to comprehend and control the interactions between the plasma and the novel metal systems to ensure that their intrinsic properties are not altered adversely for their respective technology applications.
In the framework of this PhD activity, the candidate is needed to carry out the following functions –
Required background: Masters in physics, chemistry or material science, and basic knowledge in programming
Type of work: 50% experimental, 40% modelling, 10% literature
Supervisor: Stefan De Gendt
Co-supervisor: Frederic Lazzarino
Daily advisor: Shreya Kundu
The reference code for this position is 2021-025. Mention this reference code on your application form.