Infrared Ellipsometry Investigation of Hydrogenated Amorphous Silicon

2009 ◽  
Vol 1153 ◽  
Author(s):  
Franco Gaspari ◽  
Anatoli Shkrebtii ◽  
Tom E. Tiwald ◽  
Andrea Fuchser ◽  
Shafiq Muhammad Ahmed ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Spectroscopic Ellipsometry ◽  
Spectral Region ◽  
Crystalline Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Region Of Interest ◽  
Far Infrared ◽  
Infrared Region ◽  
Infrared Ellipsometry ◽  
Hydrogenated Amorphous

AbstractHydrogenated amorphous silicon (a-Si:H) has been extensively investigated experimentally in the infrared spectral region via techniques such as Fourier Transform Infrared (FTIR) and Raman spectroscopy. Although spectroscopic ellipsometry has been proven to be an important tool for the determination of several parameters of a-Si:H films, including dielectric constant, surface roughness, doping concentration and layer thickness, the spectral range used in these studies has rarely covered the infrared region below 0.6 eV, and never over the complete spectral region of interest (0.04 – 0.3 eV). We have measured for the first time the dielectric function of a-Si:H films grown by the saddle field glow discharge technique by spectroscopic ellipsometry in the energy range from 0.04 eV to 6.5 eV, thus extending the analysis into the far infrared region. The a-Si:H films were deposited on germanium substrates for the ellipsometry studies, and on crystalline silicon substrates for the comparative FTIR analysis. Preparation parameters were chosen to obtain films with different hydrogen content. In this paper, we present the results of the ellipsometry analysis, evaluate different fitting techniques, and compare the results with the corresponding FTIR spectra. The similarities and differences between the spectra are discussed in terms of the a-Si:H properties.

scholarly journals High quality crystalline silicon surface passivation by combined intrinsic and n-type hydrogenated amorphous silicon

2011 ◽  
Vol 99 (20) ◽  
pp. 203503 ◽  
Author(s):  
Jan-Willem A. Schüttauf ◽  
Karine H. M. van der Werf ◽  
Inge M. Kielen ◽  
Wilfried G. J. H. M. van Sark ◽  
Jatindra K. Rath ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Silicon Surface ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
High Quality ◽  
Hydrogenated Amorphous ◽  
Silicon Surface Passivation

Hall-Effect and Sign Properties in Hydrogenated Amorphous and Disordered Crystalline Silicon

1996 ◽  
Vol 420 ◽  
Author(s):  
C. E. Nebel ◽  
M. Rother ◽  
C. Summonte ◽  
M. Heintze ◽  
M. Stutzmann
Keyword(s):  
Hall Effect ◽  
Amorphous Silicon ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Small Volume Fraction ◽  
Phosphorus Doped ◽  
Hydrogenated Amorphous ◽  
Defect Densities ◽  
Very High

AbstractHall experiments on a series of microcrystalline, microcrystalline-amorphous, amorphous and crystalline silicon samples with varying defect densities are presented and discussed. Normal Hall effect signatures on boron and phosphorus doped hydrogenated amorphous silicon are detected. We interpret these results to be due to a small volume fraction of nanocrystalline Si, which falls below the detection limits of Raman experiments. Hydrogenated amorphous silicon, prepared under conditions far away from microcrystalline growth, shows the known double sign anomaly, Sign reversals in c-Si, where the disorder is increased by Si implantation up to very high levels, could not be detected.

scholarly journals Anisotropy in Hydrogenated Amorphous Silicon Films as Observed Using Polarized Ftir-Atr Spectroscopy

1999 ◽  
Vol 557 ◽  
Author(s):  
J. D. Webb ◽  
L. M. Gedvilas ◽  
R. S. Crandall ◽  
E. Iwaniczko ◽  
B. P. Nelson ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Film Growth ◽  
Crystalline Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Impurity Band ◽  
Attenuated Total Reflection ◽  
Structural Anisotropy ◽  
Si Films ◽  
Polarized Ftir ◽  
Hydrogenated Amorphous

AbstractWe used polarized attenuated total reflection (ATR) measurements together with Fourier transform infrared (FTIR) spectroscopy to investigate the vibrational spectra of hydrogenated amorphous silicon (a-SiHx) films 0.5-1.0 microns in thickness. We deposited the films using hot-wire or plasma-enhanced chemical vapor deposition methods (HWCVD or PECVD, respectively) on crystalline silicon and cadmium telluride substrates. Our ATR technique gave a spectral range from 2100-400 cm-1, although the Si-H wagging mode absorption band at 640 cm-1 was somewhat distorted in the a-SiHx/Si samples by impurity and lattice absorption in the silicon ATR substrates. We report the identification of a Si-O-C impurity band with maximum intensity at 1240-1230 cm-1. The assignment of this band to a Si-O-C vibration is supported by secondary-ion mass spectrometry (SIMS) measurements. Our polarized FTIR-ATR spectra of HWCVD and PECVD a-SiHx films on <111> Si ATR substrates show that the impurity dipoles are oriented strongly parallel to the film growth direction. The wagging mode absorbance band is more intense in the film plane. This trend is less pronounced for the Si-H stretching vibrations. These observations are consistent with some degree of anisotropy or medium-range order in the films. The anisotropy in the Si-H bands may be related to residual stress in the films. Our scanning electron microscopy (SEM) analyses of the samples offer additional evidence of bulk structural anisotropy in the a-SiHx/Si films. However, the Si-O-C impurity band was not observed in the polarized ATR-FTIR spectra of the a-SiHx/CdTe samples, thus indicating that the Si substrates influence formation of the impurity in the a-SiHx/Si films.

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