Deposition of a Si monolayer on sapphire using an ArF excimer laser for Si epitaxial growth

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Abstract
Si monolayer deposition on sapphire substrates was investigated by in situ x‐ray photoelectron spectroscopy (XPS). Si deposition was carried out using direct photolysis of Si2H6 by irradiation of 193 nm ArF excimer laser light (1–2 W/cm2 , 70 Hz) at room temperature in a high‐vacuum chamber. At first, decomposed Si atoms bound strongly with O atoms on sapphire until the entire sapphire surface was covered, then SiSi bonds were formed. From the growth mode analysis of the early stage of Si deposition, it can be seen that the growth mode of the deposited layer is a layer‐by‐layer mode (the Frank–Van der Merwe‐type growth). The thickness of the deposited Si layers can be controlled on an atomic scale. As these features are suitable for Si‐on‐sapphire (SOS) epitaxial growth with predeposited layers, SOS epitaxial growth was demonstrated and the SOS films were characterized by replica electron microscopy and fabricating a metal‐oxide‐semiconductor field‐effect transistor.