We have studied the influence of SiO 2 surface properties on the nucleation and growth of silicon quantum dots ͑Si-QDs͒ deposited by SiH 4 low-pressure chemical vapor deposition ͑LPCVD͒. First, the effect of siloxane groups ͑Si-O-Si͒ strain at the SiO 2 surface layer, characterized by Fourier transform infrared ͑FTIR͒ spectroscopy, is studied. We evidenced an increase of Si-QD nucleation with the strain of siloxane groups in the SiO 2 substrate layer. Second, the Si-QD nucleation strongly depends on the surface silanol group ͑Si-OH͒ density. This density, controlled by chemical and thermal treatments, is measured by multiple internal reflexion ͑MIR͒ FTIR. Very high Si-QD densities larger than 10 12 /cm 2 are obtained on highly hydroxylated SiO 2 .During the last few years, silicon quantum dots ͑Si-QDs͒ have been studied for nanoelectronics applications. Their unique physical properties, size confinement effect, and coulomb blockade phenomena make Si-QDs suitable for use in new silicon-based devices like single electron transistors 1 or quantum dot floating gate memories. 2 For room-temperature operation of such devices, nanometric size silicon dots ͑Ͻ10 nm͒ are required.Low-pressure chemical vapor deposition ͑LPCVD͒ is a good way to obtain Si-QDs for industrial applications because of its metal-oxide field effect transistor ͑MOSFET͒ technology compatibility. By controlling the early stages of the Si film growth, silicon crystallites of nanometer size ͑5 nm͒ are obtained. 3 It has been shown that Si-QDs elaborated by SiH 4 LPCVD could exhibit coulomb blockade at room temperature 4 but to successfully integrate Si-QDs in devices their alignment must be controlled. Results were recently obtained by Baron et al. 5 who deposited an ordered array of Si-QDs by SiH 4 LPCVD on a substrate realized by wafer bonding with a periodic strain field at the surface.In order to obtain operating devices, size, size uniformity, and Si-QDs density must also be controlled with great precision and reproducibility. For floating gate memory applications, densities between 10 11 and 10 12 /cm 2 are required. To fabricate a single electron transistor with a lateral current transport, the spacing between dots should be lower than 2 nm. Typically, for a dot size of 5 nm, these conditions lead to a density of 3 ϫ 10 12 Si-QDs/cm 2 . 6 Si-QD size and density are piloted by pressure and temperature conditions. The chemical nature of the substrates 3 and its physical properties such as stress, roughness, or defects can play an important role in silicon nucleation. Voutsas and Hatalis 7 showed that the chemical properties of the SiO 2 surface also strongly affect the first stages of silicon deposition.In this paper, we separately investigated the influence of ͑i͒ the strain of siloxane ͑Si-O-Si͒ groups and ͑ii͒ the surface silanol ͑Si-OH͒ density on thermally grown SiO 2 layers on Si-QD nucleation by SiH 4 LPCVD. These characteristics are controlled by the oxidation process and postoxidation chemical and thermal treatments, respectively. Experim...
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