Observation of a (2 times 8) surface reconstruction on Si sub 1-x Ge sub x alloys grown on (100) Si by molecular-beam epitaxy

Conference · · Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena; (United States)

OSTI ID:7306036

Croke, E T; Fu, T C; McGill, T C ^[1]; Hauenstein, R J ^[2]

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1. California Inst. of Tech., Pasadena (United States)
2. Hughes Research Labs., Malibu, CA (United States)

The authors present evidence supporting the formation of a new, (2 {times} 8) surface reconstruction on Si{sub 1-x}Ge{sub x} alloys grown on (100) Si substrates by molecular-beam epitaxy. Surfaces of Si{sub 1-x}Ge{sub 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 550C, exhibit n/8 fractional-order diffraction streaks in addition to the normal (2 {times} 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 {times} 1) reconstruction. The authors examined the thermal stability of the (2 {times} 8) reconstruction and have found that it reverts to (2 {times} 1) after annealing to 700C and reappears after the sample temperature is allowed to cool below 600C. 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 {times} 1) reconstruction. They present a simulation in the kinematic approximation, confirming the validity of their interpretation of these findings.

• OSTI ID: 7306036
• Report Number(s): CONF-910115-; CODEN: JVTBD
• Journal Information: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena; (United States), Vol. 9:4; Conference: 18. annual conference on physics and chemistry of semiconductor interfaces, Long Beach, CA (United States), 29 Jan - 1 Feb 1991; ISSN 0734-211X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
GERMANIUM ALLOYS
CRYSTAL STRUCTURE
MOLECULAR BEAM EPITAXY
SILICON ALLOYS
ANNEALING
ELECTRON DIFFRACTION
SILICON
SUBSTRATES
TEMPERATURE RANGE 0400-1000 K
ALLOYS
COHERENT SCATTERING
DIFFRACTION
ELEMENTS
EPITAXY
HEAT TREATMENTS
SCATTERING
SEMIMETALS
TEMPERATURE RANGE
360602* - Other Materials- Structure & Phase Studies