Stress characterization of thin microcrystalline silicon films

K. Christova , S. Alexandrova , A. Abramov , E. Valcheva , B. Ranguelov , Christophe Longeaud (1) , Steve Reynolds , Pere Roca I Cabarrocas

1 LGEP - Laboratoire de génie électrique de Paris

Hydrogenated microcrystalline silicon (�c-Si:F:H) films in the thickness range 10 to 200 nm have been studied in order to reveal stress in the early stages of deposition and to correlate it with the crystalline microstructure. Stress characterization has been implemented using Raman spectroscopy and wafer curvature measurements. Together, these fix the value of Raman Mechanical Coefficient for �c-Si:F:H thin films at -1.4x10-5 (cm-1/MPa). This constant characterizes the film properties resulting from the growth process. Raman spectra also indicate the presence of defective nanocrystallites that may contribute to crystalline phase formation. This result is discussed in the light of stress evolution. The characterization includes Scanning Electron Microscopy (SEM) analysis to estimate the grain size in the films.

K. Christova, S. Alexandrova, A. Abramov, E. Valcheva, B. Ranguelov, et al.. Stress characterization of thin microcrystalline silicon films. International Review of Physics, 2012, 6 (1), pp.106. ⟨hal-00778965⟩