Journal of Thermal Analysis and Calorimetry, Vol. 76 (2004) 685–691
GROWTH OF SILICON THIN FILM BY LPE ON
POROUS SILICON BILAYERS
A. Ould-Abbas
1*
, M. Bouchaour
1
, N.-E. Chabane-Sari
1
, S. Berger
2
,
A. Kaminski
2
and A. Fave
2
1
Laboratoire des Matériaux et Energies Renouvelables, Université de Tlemcen,
BP 119 Tlemcen 13000, Algérie
2
Laboratoire de Physique de la Mati Àre, UMR-CNRS 5511, Institut National des Sciences
Appliquées de Lyon, Bât. B. Pasc l, 7 avenue Jean Capelle, 69621 Villeurbanne Cedex, France
Abstract
The fabrication of solar cells based on the transfer of a thin silicon film on a foreign substrate is an
attractive way to realise cheap and efficient photovoltaic devices. The aim of this work is to realise a
thin mono-crystalline silicon film on a double porous silicon layer in order to detach and transfer it
on mullite. The first step is the fabrication of a double porous silicon layer by electrochemical
anodisation using two different current densities. The low current leads to a low porosity layer and
during annealing, the recrystallisation of this layer allows epitaxial growth. The second current leads
to a high porosity which permits the transfer on to a low cost substrate. Liquid Phase Epitaxy (LPE)
performed with indium (or In+Ga) in the temperature range of 950–1050°C leads to almost homoge-
neous layers. Growth rate is about 0.35 μm min
–1
. Crystallinity of the grown epilayer is similar on
porous silicon and on single crystal silicon. In this paper, we focus on the realisation of porous sili-
con sacrificial layer and subsequent LPE growth.
Keywords: c-Si, LPE, porous silicon
Introduction
The prices of photovoltaic energy devices have to be decreased to be competitive
compared with other low cost ones. About half of the price of photovoltaic silicon
modules is due to the silicon wafers. A solution to decrease material cost consists in
transferring a thin epitaxial silicon film on to a ceramic or glass substrate [1–5]. In
this process, a thin porous silicon sacrificial layer (realised on the top of a silicon wa-
fer) allows epitaxial growth and the removal of the epilayer from the substrate, which
can be reused several times. In this study, we report liquid phase epitaxial growth on
porous silicon at different temperatures and on different porous silicon samples. Po-
rosity of samples is detected by gravimetry, ellipsometric and gas adsorption mea-
surements. Scanning electron microscope (SEM) analysis have been carried out in
order to study p-Si evolution vs. temperature, LPE layer thickness and morphology.
1388–6150/2004/ $ 20.00
© 2004 Akadémiai Kiadó, Budapest
Akadémiai Kiadó, Budapest
Kluwer Academic Publishers, Dordrecht
* Author for correspondence: E-mail: a_ouldabbes@mail.univ-tlemcen.dz