S. Ostapenko et al., ENHANCED HYDROGENATION IN POLYCRYSTALLINE SILICON THIN-FILMS USING LOW-TEMPERATURE ULTRASOUND TREATMENT, Applied physics letters, 68(20), 1996, pp. 2873-2875
Ultrasound treatment (UST) was applied to improve electronic propertie
s of polycrystalline silicon films on silica-based substrates, A stron
g decrease of sheet resistance by a factor of two orders of magnitude
was observed in hydrogenated films at UST temperatures lower than 100
degrees C. This is accompanied by improvement of a film homogeneity as
confirmed by spatially resolved photoluminescence study. The UST effe
ct on sheet resistance demonstrates both stable and metastable behavio
r. A stable UST effect can be accomplished using consecutive cycles of
UST and relaxation. An enhanced passivation of grain boundary defects
after UST is directly measured by nanoscale contact potential differe
nce with atomic force microscope. Two specific UST processes based on
interaction between the ultrasound and atomic hydrogen are suggested:
enhanced passivation of grain boundary defects and UST induced metasta
bility of hydrogen related defects. (C) 1996 American Institute of Phy
sics.