SIS on ultra-thin PMMA for high-k deposition on 2D materials and selective high-k plasma etch and soft-landing onto 2D materials

The proposed work-package aims at high-k processing for 2D materials applications. The main objective of the internship is to study the synthesis of 3-4nm high-k dielectric (corresponding to 1 nm EOT) using a sacrificial template, based on porous polymer (polymethylmetacrylate/PMMA or polyphtalaldehyde/PPA) combined with sequential infiltration synthesis (SIS). The principle will use the following sequence: first, spin-coat 3-5 nm of polymer; second, infiltrate the polymer with a specific Al(CH₃)₃/H₂O ALD sequence forming Al₂O₃ within the bulk of the polymer; third, perform some post-treatments in order to remove the residual carbon from the formed composite film. Post-treatments will be based on annealing, UV-cure, and/or downstream plasma processing. A second objective is to support some technological etch process aiming at etching high-k (10nm ZrO₂) stopping on a sub-nm SiO₂ on top of WS₂, using a BCl₃/O₂ cyclic process in a state-of-the art 300mm plasma etch chamber. The goal of the process is to remove the whole dielectric stack (ZrO₂ + SiO₂) with minimal damage to the WS₂. Screening of plasma chemistries (BCl₃/O₂ ratio, potential additives), plasma physical parameters (pressure, power, bias) and sequences (plasma cycles) will be investigated; the etch and selectivity mechanisms will be studied using ellipsometry, AFM, Raman and photoluminescence spectroscopy.​