Understanding Surface-Controlled Thin Film Growth Using Area-Selective Deposition

As semiconductor devices continue to scale towards increasingly complex three-dimensional architectures, conventional blanket deposition processes face significant challenges related to material placement, process complexity, and manufacturing cost. Area-selective deposition (ASD) has emerged as a promising approach that enables material growth exclusively on predefined regions of a substrate while preventing deposition on neighboring areas. This capability can reduce process steps, simplify fabrication flows, and improve patterning precision.

A key enabler of successful ASD is surface passivation, where carefully engineered surface treatments or inhibitor layers suppress nucleation and growth on non-target regions. Different passivation strategies, including self-assembled monolayers, polymer-based inhibitors, plasma treatments, and chemical functionalization methods, can significantly influence deposition selectivity, nucleation behavior, and long-term process stability.

Objectives

The objective of this thesis is to investigate the interplay between area-selective deposition and surface passivation techniques for the controlled growth of thin films on technologically relevant substrates.

The student will:

• Review the state-of-the-art in area-selective deposition and surface inhibition mechanisms.
• Study surface chemistry and nucleation behavior on different material surfaces.
• Develop and optimize passivation strategies to selectively suppress film growth.
• Evaluate deposition processes such as Atomic Layer Deposition (ALD), Chemical Vapor Deposition (CVD), or related techniques.
• Quantify deposition selectivity using advanced characterization methods.
• Identify mechanisms responsible for selectivity loss and develop mitigation strategies.
• Assess the suitability of the developed process for future nanoelectronic, photonic, or energy-related applications.

Possible tasks include:

• Surface preparation and passivation experiments.
• Thin-film deposition using ALD, CVD, ....
• Interpretation of surface characterization using techniques such as:
  • X-ray Photoelectron Spectroscopy (XPS)
  • Spectroscopic Ellipsometry
  • Contact Angle Measurements
  • Scanning Electron Microscopy (SEM)
  • Atomic Force Microscopy (AFM)
  • Energy Dispersive X-ray Spectroscopy (EDS)
• Analysis of nucleation delay and growth kinetics.
• Correlation of surface chemistry with deposition selectivity.
• Data analysis and process optimization.

Expected Outcomes

The thesis is expected to provide:

• Fundamental understanding of surface passivation mechanisms.
• Improved insight into selective nucleation and film growth processes.
• A quantified assessment of deposition selectivity.
• Recommendations for implementing selective deposition processes in advanced device fabrication.
• Potential pathways for extending ASD concepts towards future semiconductor manufacturing technologies.