AVS 54th International Symposium
    Thin Film Tuesday Sessions
       Session TF-TuA

Paper TF-TuA8
Passivation and Atomic Layer Deposition on Halide-Terminated Ge Surfaces

Tuesday, October 16, 2007, 4:00 pm, Room 613/614

Session: Surface Chemistry for Atomic Layer Deposition
Presenter: P. Ardalan, Stanford University
Authors: P. Ardalan, Stanford University
C.B. Musgrave, Stanford University
S.F. Bent, Stanford University
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Because of the poor oxide of germanium, alternative passivation methods are required for practical use of Ge in devices. We have studied the passivation of germanium surfaces by alkanethiolate self-assembled monolayers (SAMs) and by ALD-deposited titanium dioxide (TiO2). We have also investigated the ability of the SAMs to block TiO2 deposition for application to area selective ALD. Our studies started with halide-terminated (Cl- or Br-) Ge(100) and (111) surfaces, which have been shown to exhibit good stability and resistance to oxidation. The initial functionalization of Ge surfaces by HCl and HBr was investigated by various experimental and theoretical methods, including x-ray photoelectron spectroscopy and density functional theory. Next, these surfaces were exposed to 1-alkanethiols to form alkanethiolate self-assembled monolayers (SAMs), where the formation and bonding of such SAMs were studied by the same methods. We also investigated the ALD of TiO2 on halide-terminated Ge surfaces, with the results showing a strong temperature dependence of the growth process. Finally, we have explored the area selective ALD of TiO2 at the Ge surfaces. We observe that the 1-alkanethiolate SAMs protect the Ge surfaces from ALD, leaving TiO2 to deposit only at regions of the Ge surfaces which are functionalized by halides but not protected by the SAMs. The results demonstrate a new route to Ge surface functionalization and passivation.