Some aspects of substrate pretreatment for epitaxial Si nanowire growth

Abstract

We report on the influence of the surface pretreatment for vapor-liquid-solid growth of epitaxial silicon nanowires with gold catalyst and silane precursor on Si(111) substrates. In this paper we make it obvious that a thin native oxide layer on the Si substrate-as is present under most technological conditions-or a thin layer of oxide formed on top of the catalytic gold particle restrain nucleation and nanowire growth. High resolution transmission electron microscopy, and electron energy loss spectroscopy were utilized to demonstrate Si diffusion from the substrate through the catalytic Au layer and further the formation of a thin oxide layer atop. Based on this observation we present a sample pretreatment practice, making the catalyst insensitive for further oxide formation, thereby preserving epitaxy for nanowire synthesis.

Au-Catalyzed Silicon Nanoneedles Synthesized from Pure Silane Gas at Various RF Powers on Silicon Substrate by VHF-PECVD

“…This value is significantly higher than the usual growth rates (10-50 nm/min) of Si nanowires grown by CVD, low pressure CVD and conventional medium frequency of 13.56 MHz PECVD methods [25][26][27][28]. This higher growth rate is probably due to plasma power which causes high decomposition of the SiH 4 gas.…”

Growth of one-dimensional III–V structures on Si nanowires and pre-treated planar Si surfaces

“…This is different for the growth of GaAs whiskers on Si nanowires. Surprisingly in contrast to the LP-CVD growth of Si nanowires on Si, removing the oxide before sputter deposition suppressed the growth of GaAs nanowires on Si [6].…”

“…However, the challenge is to achieve control over the positioning as well as diameters and length of these nanowires. The locations of the nanowires are most often defined by lithographic steps [4], while the orientation of the wires depends on growth parameters catalyst size and precursor pressure [5,6].…”

Influence of growth time on morphology and structural properties of silicon nanowires grown by VHF-PECVD

“…A comparison between the growth of Si nanoneedles/nanowires by VHF-PECVD, LPCVD [35] and conventional PECVD Fig. 3.…”