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Observation of a (2X8) surface reconstruction on Si_(1-x)Ge_x alloys grown on (100) Si by molecular beam epitaxy

Croke, E. T. and Hauenstein, R. J. and Fu, T. C. and McGill­, T. C. (1991) Observation of a (2X8) surface reconstruction on Si_(1-x)Ge_x alloys grown on (100) Si by molecular beam epitaxy. Journal of Vacuum Science and Technology B, 9 (4). pp. 2301-2306. ISSN 1071-1023. doi:10.1116/1.585737.

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We present evidence supporting the formation of a new, (2×8) surface reconstruction on Si_(1−x)Ge_x alloys grown on (100) Si substrates by molecular‐beam epitaxy. Surfaces of Si_(1−x)Ge_x alloys were studied using reflection high‐energy electron diffraction (RHEED) and low‐energy electron diffraction (LEED) techniques. RHEED patterns from samples with Ge concentrations, x, falling within the range 0.10–0.30 and grown at temperatures between 350 and 550 °C, exhibit n/8 fractional‐order diffraction streaks in addition to the normal (2×1) pattern seen on (100) Si. The presence of fractional‐order diffracted beams is indicative of an eight‐fold‐periodic modulation in electron scattering factor across the alloy surface. LEED patterns from surfaces of samples grown under similar conditions are entirely consistent with these results. In addition, the LEED patterns support the conclusion that the modulation is occurring in the direction of the dimer chains of a (2×1) reconstruction. We have examined the thermal stability of the (2×8) reconstruction and have found that it reverts to (2×1) after annealing to 700 °C and reappears after the sample temperature is allowed to cool below 600 °C. Such behavior suggests that the reconstruction is a stable, ordered phase for which the pair‐correlation function of surface Ge atoms exhibits an eightfold periodicity in the "1" direction of a Si‐like (2×1) reconstruction. We also present a simulation in the kinematic approximation, confirming the validity of our interpretation of these findings

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Additional Information:© 1991 American Vacuum Society. Received 2 February 1991; accepted 11 April 199l. One of us, E. T. Croke, would like to acknowledge International Business Machines Corporation for support under a graduate research fellowship. In addition, the authors would like to acknowledge the partial support of the Office of Naval Research under Grant No. N00014-89-J-3196.
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Office of Naval Research (ONR)N00014-89-J-3196
International Business Machines Corporation graduate research fellowshipUNSPECIFIED
Issue or Number:4
Classification Code:PACS: 68.55.-a, 81.15.Hi, 61.05.jh
Record Number:CaltechAUTHORS:20120418-154233164
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Official Citation:Observation of a (2×8) surface reconstruction on Si1−xGex alloys grown on (100) Si by molecular‐beam epitaxy E. T. Croke, R. J. Hauenstein, T. C. Fu, and T. C. McGill J. Vac. Sci. Technol. B 9, 2301 (1991);
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:30187
Deposited By: Ruth Sustaita
Deposited On:19 Apr 2012 14:20
Last Modified:09 Nov 2021 19:39

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