Dissociative Adsorption of SiH₂Cl₂ on Si(111)7×7

Fabrication of surface nanostructures by scanning tunneling microscope induced decomposition of SiH4 and SiH2Cl2

“…The 7ϫ7 structure is modified insofar as a fraction of the adatoms is darkened. The appearance of this part of the surface is identical to that of the Si͑111͒7ϫ7 surface after interaction with DCS at room temperature, 21 indicating that tip induced deposition is limited to a very narrow area with a diameter of about 150 Å in Fig. 1͑a͒.…”

“…All deposition and subsequent imaging were performed at room temperature, where normal dissociative adsorption of MS and DCS precursor molecules saturates after submonolayer coverage. 20,21 …”

“…By holding the tip at constant position and by careful optimization of the deposition parameters it is possible to deposit spotlike structures on the surface. Since the surface modifications caused by dissociative adsorption of the precursor gases SiH 4 or DCS with Si͑111͒7ϫ7 at room temperature have been studied in detail earlier 20,21 and are well known, STM induced depositions can be unambiguously identified on the surface.…”

Chlorosilane adsorption on clean Si surfaces: Scanning tunneling microscopy and Fourier-transform infrared absorption spectroscopy studies

“…Interaction of SiH 2 Cl 2 with Si surfaces is not only of importance for atomic-scale control of Si epitaxial growth, but also of interest as a basic adsorption system. The adsorption of SiH 2 Cl 2 on Si͑111͒ and Si͑100͒ surfaces have been studied by a variety of experimental and theoretical methods such as time-of-flight scattering and recoiling spectroscopy, 1 desorption spectroscopy, 2,3 x-ray photoemission spectroscopy ͑XPS͒, 4,5 Auger electron spectroscopy, 5 scanning tunneling microscopy ͑STM͒, 5,6 and ab initio molecular orbital calculation. 7 These studies showed that SiH 2 Cl 2 chemisorbs on the Si͑111͒-͑7ϫ7͒ and Si͑100͒-͑2ϫ1͒ surfaces even at room temperature.…”

“…For adsorption on the Si͑111͒-͑7ϫ7͒ surface, structure models proposed so far have an-SiH 2 Cl group and a Cl atom as dissociation products of the SiH 2 Cl 2 molecule. 5,6 However, the presence of the -SiH 2 Cl group was determined from the Fourier-transform infrared absorption spectroscopy ͑IRAS͒ results on porous silicon. 8 No direct evidence has been obtained yet for the presence of the -SiH 2 Cl group on the Si ͑111͒-͑7ϫ7͒ surface.…”