Interaction of SiH4 with Si(100)2×1 and with Si(111)7×7 at 690 K: A comparative scanning tunneling microscopy study

Abstract

We have studied the interaction of SiH4 with Si(100)2×1 and with Si(111)7×7 utilizing scanning tunneling microscopy. At 690 K Si deposition does not saturate, but the reactive sticking coefficient is considerably larger for Si(100)2×1. On this surface the 2×1 reconstruction is preserved during deposition. The anisotropy of the newly formed islands and the growth process are influenced by the presence of hydrogen from dissociated SiH4. In contrast, the Si(111)7×7 surface is completely restructured by the interaction with SiH4. This results in the formation of a bulklike hydrogen terminated 1×1 structure without any remnants of stacking faults. After exposure to 50 000 L SiH4 at 690 K not more than half a bilayer has grown, forming triangular Si(111)1×1-H islands.

The role of antiphase domain boundaries in Si epitaxy by ultrahigh vacuum chemical vapor deposition from SiH 4 or SiH 2 Cl 2 on Si(100)-(2×1)

“…The STM experiments were performed in an ultrahigh vacuum (UHV) surface analysis system described in detail elsewhere [2]. It is equipped with a home-built pocket-size STM and standard surface analysis equipment (Auger electron spectrometer, quadrupole mass spectrometer).…”

“…Experimentally, intermediate behavior is frequently observed during growth under MBE as well as under CVD conditions, where interlayer transport is possible to a certain extent. This results in nucleation of new layers before the underlying layers are completely filled [1,2,4]. Under these conditions reflectance high-energy electron diffraction (RHEED) intensity oscillations of reduced amplitude can be observed if the rate of interlayer transport is sufficiently high.…”

“…Under these conditions multilayer growth is governed by heterogeneous nucleation of dimer strings at antiphase domain boundaries of the underlying layer which represent deep potential minima for diffusing species. This is in contrast to the formation of the first epitaxial layer, which nucleates homogeneously on the flat substrate terraces.If silicon chemical vapor deposition (CVD) on Si(100)-(2 × 1) is carried out in an intermediate temperature and pressure regime, epitaxy proceeds by island nucleation and growth [1,2]. The evolution of the surface topography in this intermediate regime depends on the extent of interlayer transport.…”

“…If silicon chemical vapor deposition (CVD) on Si(100)-(2 × 1) is carried out in an intermediate temperature and pressure regime, epitaxy proceeds by island nucleation and growth [1,2]. The evolution of the surface topography in this intermediate regime depends on the extent of interlayer transport.…”

Thermal decomposition of tetraethoxysilane (TEOS) on Si(111)-(7×7)

“…STM images are presented in a top view representation, with darker tones corresponding to deeper levels on the sample. The Si(111) samples are p-type boron doped with a resistivity of 1-20 Ωcm and cleaned using standard sample cleaning and preparation techniques as described previously [8]. Commercially available TEOS (Aldrich, +99.9%) was further cleaned by freeze-pump-thaw cycles prior to use.…”