/Revealing the relationship between the precursors used in atomic layer deposition and the electron mobility in two-dimensional materials

Revealing the relationship between the precursors used in atomic layer deposition and the electron mobility in two-dimensional materials

PhD - Leuven | More than two weeks ago

You will unlock material chemistry challenges to enable the development of material innovation in tomorrow’s memory and logic nanoelectronic devices through a unique international project.  

Novel two-dimensional materials, and especially semi-conducting transition metal dichalcogenides (MX2, with M being a transition metal and X a chalcogen) offer advanced functionality in complex and ultra-scaled integrated systems. In view of their compelling electronic and electrical performances as an atomically thin monolayer, imec explores their integration for various applications and systems, in particular for advanced CMOS and memory technologies in a beyond silicon roadmap. The deposition of high-quality materials is highly challenging due to the high aspect ratios requirements of advanced 3D architectures. Atomic Layer Deposition (ALD) is a promising technique in this respect, as it can in principle enable conformal deposition on 3D structures with a thickness and composition control at the atomic level. 
However, ALD of MX2 materials generally suffer from poor control over crystallinity and crystal grain size, hindering their electrical performance in semiconductor devices [1]. Inhibitor molecules open a new avenue to control the growth behavior and resulting material properties through tailoring the reactivity of the starting surface [2]. Understanding how the chosen ALD precursor and inhibitor model determine the MX2 nucleation and growth behavior and affects the MX2 electrical performance on both blanket and patterned substrates remain poorly understood to date. 
In this project, the Ph.D. candidate will contribute to an international effort that blends modelling insights, chemical precursor design and on-scale demonstration to address the growth and material challenges. He/she will perform his/her Ph.D. through a shared position between the MX2 growth team of imec and the department of Chemistry at University of Helsinki. The candidate will combine chemical reactivity insights with physical and chemical characterization techniques in the exploration of new inhibitors and chalcogenide and metal precursors.  The insights in the nucleation mechanisms will be used to design strategies to improve the nucleation control and as such the structural quality of ALD deposited MX2 films. The semiconductor properties of the resulting films will then be tested on nanoscale patterned structures fabricated in imec. 
The project will leverage the ALD center Finland research infrastructurewith both the imec 300mm production and atomistic modelling platforms for advanced node CMOS technologies to identify new precursors and to grow conformal MX2 films on patterned structures with topography and dimensions down to tens of nanometres. 
[1] M. Mattinen et al., Adv. Mater. Interfaces 2021, 8, 2001677
[2] W. Jeon et al., Adv. Mater. 2017, 29, 1703031

Required background: Chemistry, Physics, Materials, Nanotechnology  

Type of work: 10% literature study, 90% experimental work  

Supervisor: Annelies Delabie

Co-supervisor: Benjamin Groven

Daily advisor: Benjamin Groven & Pierre Morin

The reference code for this position is 2022-136. Mention this reference code on your application form.