login

Search documents

Browse topics

Document details

 
Title:
 
Modeling of Horizontal Pore Channeling During High Temperature Annealing of Porous Silicon With Initial Vertical Columnar Macropores
 
Author(s):
 
M.Y. Ghannam, M.M. Hassan, V. Depauw, G. Beaucarne, J. Poortmans, R. Mertens
 
Topic:
 
Thin Films
Subtopic: Thin Film Crystalline Silicon
Event: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain
Session: 3AV.1.7
 
Pages:
 
2205 - 2208
ISBN: 3-936338-24-8
Paper DOI: 10.4229/23rdEUPVSEC2008-3AV.1.7
 
Price:
 
 
0,00 EUR
 
Document(s): paper
 

Abstract/Summary:


Horizontal channeling between neighboring pores in porous silicon during high temperature annealing is successfully modeled. The finite element solution of the force balance equation governing the change in the material morphology during high temperature annealing is carried out in the transient mode for the different stages of the annealing process. It is shown that during the temperature ramp up stage the as-formed columnar pores change to quasi-spherical bubbles as a result of the competition between the thermal stress and the initial residual stress. The resulting stress during this stage is dominated by the horizontal component, leading to horizontal channeling between neighboring pores. The channels form during subsequent constant temperature annealing stage with the absence of any thermal stress, and are separated by thin vertical silicon straps. Finally, during temperature ramp down, the thermal stress and the residual stress act together helping the pores to grow. During this stage the straps may break and thin silicon films can be liberated.