Point defect–dislocation interactions in BEOL-compatible Ge-on-Si epitaxy
Name
031103_1_5.0153230.pdf
Description
Published version
Size
1.81 MB
Format
Adobe PDF
Checksum (MD5)
348b66f129bc73565fb83b5fcbbae087
Author(s)
Postelnicu, Eveline
Wen, Rui-Tao
Ma, Danhao
Wang, Baoming
Wada, Kazumi
Michel, Jurgen
Kimerling, Lionel C
Date Issued
July 17, 2023
Journal
Applied Physics Letters
Publisher
AIP Publishing
Citation
Eveline Postelnicu, Rui-Tao Wen, Danhao Ma, Baoming Wang, Kazumi Wada, Jurgen Michel, Lionel C. Kimerling; Point defect–dislocation interactions in BEOL-compatible Ge-on-Si epitaxy. Appl. Phys. Lett. 17 July 2023; 123 (3): 031103.
Version
Final published version
Abstract
Reduced thermal budget is required for back-end-of-line (BEOL) integration of application specific functionality into the multilevel metal stack of a processor “substrate.” We report 400 °C BEOL-compatible Ge-on-Si growth (LT Ge) that is epitaxial and single crystalline with a defect density similar to high temperature growth and a small 0.05% tensile strain. Room temperature methanol–iodine passivation is employed pre-growth in lieu of the typical 800 °C oxide removal step. Undoped LT Ge exhibits p-type conductivity initially and n-type conductivity conversion upon annealing. Hall effect measurements following post growth heat treatment between 400 and 600 °C reveal an acceptor removal reaction that follows first-order kinetics with an activation energy of 1.7 ± 0.5 eV and a pre-exponential factor of 2.3×107 s−1 consistent with a point defect, diffusion limited process. We also observe that 90° sessile dislocations identified via transmission electron microscopy are annihilated in the same temperature regime, which is evidence for point defect-mediated climb. Ensuring high-quality epitaxy by characterizing defect reactions in a BEOL-compatible Ge-on-Si process flow is key to enabling vertical integration of optical interconnects.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Terms of Use
Creative Commons Attribution
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1063/5.0153230
