IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Electronics Wednesday Sessions
       Session EL-WeA

Invited Paper EL-WeA1
Epitaxial Growth by Low-energy Plasma-enhanced CVD

Wednesday, October 31, 2001, 2:00 pm, Room 124

Session: Semiconductor Growth
Presenter: H. von Känel, ETH Zürich, Switzerland
Authors: H. von Känel, ETH Zürich, Switzerland
M. Kummer, Interstate University of Applied Science, Switzerland
A. Dommann, Interstate University of Applied Science, Switzerland
C. Rosenblad, Unaxis Semiconductors, Liechtenstein
J. Ramm, Unaxis Semiconductors, Liechtenstein
T. Hackbarth, Daimler Chrysler Research Center, Germany
M. Zeuner, Daimler Chrysler Research Center, Germany
Correspondent: Click to Email
Epitaxial growth of Si and SiGe by a low-energy plasma-enhanced CVD (LEPECVD) process is described. LEPECVD is based on a low voltage DC arc discharge, leading to very efficient decomposition of the gaseous precursors SiH@sub 4@ and GeH@sub 4@. In addition, direct immersion of the substrate in the intense plasma strongly enhances surface kinetics in particular at low growth temperatures. As a result, epitaxial growth rates in LEPECVD can be as high as 10 nm/s, nearly independent of the substrate temperature in the range between 500°C and 750°C. LEPECVD is ideally suited for the growth of SiGe-MODFET and SiGe-MOSFET structures, requiring thick graded Si@sub 1-x@Ge@sub x@ buffer layers with low defect densities. Concentration profiles are easy to control because Ge incorporation is entirely determined by the germane to silane flux ratio. X-ray reciprocal space mapping, defect etching and scanning force microscopy have been used to characterize buffers grown with Ge end concentrations between 10 % and 100 %. LEPECVD combined with other low temperature growth techniques, such as molecular beam epitaxy (MBE) has been shown to lead to superior performance of n-channel MODFETs.@footnote 1@ Alternatively, the growth rates in LEPECVD can be lowered in order to allow for the synthesis of active channels with abrupt interfaces by this technique alone. Examples will be shown with strained Ge-rich channels up to 100 % Ge on relaxed buffers with Ge end concentrations between 50 and 70 %. Such structures have given rise to p-MOSFETs with effective hole mobilities exceeding the one of standard Si p-MOSFETs by up to a factor of four @footnote 2@. @FootnoteText@ @footnote 1@ T. Hackbarth et al., 11@super th@ European Workshop on Molecular Beam Epitaxy, Hinterzarten, Germany, 02/06/01. @footnote 2@ G. Höck et al., Appl. Phys. Lett. 76, 3920 (2000).