Films minces à base de Si nanostructuré pour des cellules ...

Chapter 3
A study on RF sputtered SRSO monolayers and
SRSO/SiO 2 multilayers
tel-00916300, version 1 - 10 Dec 2013
3.1 Introduction
One of the major aims of this thesis, as mentioned in chapter 1, is to increase the
density of Si-nanoparticles (Si-np) with regard to the team's earlier obtained value
of 9 x10 18 np/cm 3 [Maestre 10]. Optimizing the growth parameters of SRSO 1 is an
important step towards accomplishing this increase of density. Prior works on SRSO
grown either by co-sputtering of SiO 2 target topped with Si chips placed at the target
surface [Charvet 99] or by reactive sputtering [Ternon 02] have been done in our
laboratory, using another RF magnetron sputtering unit 'MECA 2000'. With the
sputtering unit AJA International used in this thesis, initial studies were performed
with the values of plasma pressure controlled with buttery valve, substrate-target
distance and the substrate rotation speed of 3 mTorr, 38 cm and 20 rpm respectively.
These values were conrmed by [Hijazi 09b] while studying SRSO: Er materials in
which SRSO was grown by the co-sputtering of SiO 2 and Si. Hence these values
have been adopted for all our depositions. Three methods using confocal sputtering
technique are developed in our team to introduce excess Si to form SRSO. The rst
two methods are the same as those used by Ternon, (Reactive sputtering which will
be investigated in AJA now) and Hijazi (co-sputtering) for their thesis in the references
cited above. The third method, 'Reactive co-sputtering' is a newly introduced
concept in this thesis, combining the advantages of the two other aforesaid methods.
The SRSO monolayers grown using these three methods are studied with respect
to deposition rate r d , refractive index n and structural composition. Optimized
1 SRSO will be occasionally denoted as SiO x in the text
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