Effect of Ion Energy on Microcrystalline Silicon Material and Devices: A Study Using Tailored Voltage Waveforms

Author

Bruneau, Bastien ; Lepecq, Michael ; Junkang Wang ; Dornstetter, Jean-Christophe ; Maurice, Jean-Luc ; Johnson, Erik V.

Author_Institution

Lab. de Phys. des Interfaces et des Couches Minces, Ecole Polytech., Palaiseau, France

Volume

4

Issue

6

fYear

2014

fDate

Nov. 2014

Firstpage

1354

Lastpage

1360

Abstract

The use of tailored voltage waveforms to excite a plasma has been shown to be an effective technique to decouple maximum ion energy from the ion flux on the electrode. We use it here as a way to scan through the maximum ion energy in order to study this quantity´s role in the growth of μc-Si:H. We find that at critical energies (30 and 70 eV), a stepwise increase in the a-Si:H/μc-Si:H transition thickness is observed, together with change in the surface morphology. These thresholds correspond to SiH_x⁺- and H₃⁺ -induced displacement energies, respectively. A model is proposed to account for the impact of these ions on the morphology of μc-Si:H growth and is confirmed by comparison with epitaxial growth on a crystalline wafer.

Keywords

crystallisation; elemental semiconductors; epitaxial growth; hydrogen; ion beam effects; ion-surface impact; semiconductor epitaxial layers; semiconductor growth; silicon; surface morphology; Si:H; crystal growth; displacement energies; electron volt energy 30 eV; electron volt energy 70 eV; epitaxial growth; ion energy effect; microcrystalline silicon material; surface morphology; tailored voltage waveforms; transition thickness; Crystalline materials; Epitaxial growth; Ions; Silicon; Surface morphology; Surface treatment; Growth model; ion bombardment energy; microcrystalline silicon; tailored voltage waveform;

fLanguage

English

Journal_Title

Photovoltaics, IEEE Journal of

Publisher

ieee

ISSN

2156-3381

Type

jour

DOI

10.1109/JPHOTOV.2014.2357259

Filename

6912935