Spectroscopic Ellipsometry and Interference Reflectometry Measurements of CVD Silicon Grown on Oxidized Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
G. E. Jellison ◽  
M. Keefer ◽  
L. Thornquist
Keyword(s):  
Thin Film ◽  
Surface Roughness ◽  
Spectroscopic Ellipsometry ◽  
Surface Region ◽  
Near Surface ◽  
Optical Functions ◽  
Constant Angle ◽  
Thin Film Silicon ◽  
Amorphous Si

ABSTRACTSeveral samples of thin-film silicon grown on oxidized Si, both oxidized and unoxidized, have been examined using spectroscopie ellipsometry (SE) and constant angle reflection interference spectroscopy (CARIS). The SE data was fit to 5- or 6- layer models of the sample near-surface region, using the optical functions of thin-film silicon determined from a previous work. Reasonable fits were obtained from samples containing amorphous Si (a-Si) or large-grain poly-crystalline Si (p-Si), but fits to samples containing small-grain, undoped p-Si were poor unless a 8–15 nm surface roughness layer is included. Furthermore, the optical functions of p-Si:ud are not consistent from sample to sample. The optical functions determined from SE measurements were then used to interpret CARIS measurements, extracting the thicknesses of the films, which are then compared with the thicknesses obtained from SE.

Amorphous Silicon, Microcrystalline Silicon, and Thin-Film Polycrystalline Silicon Solar Cells

MRS Bulletin ◽  
2007 ◽  
Vol 32 (3) ◽  
pp. 219-224 ◽  
Author(s):  
Ruud E.I. Schropp ◽  
Reinhard Carius ◽  
Guy Beaucarne
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Crystalline Silicon ◽  
Low Cost ◽  
Float Glass ◽  
Film Material ◽  
Microcrystalline Silicon ◽  
Plastic Substrates ◽  
Thin Film Silicon ◽  
Amorphous Si

AbstractThin-film solar cell technologies based on Si with a thickness of less than a few micrometers combine the low-cost potential of thin-film technologies with the advantages of Si as an abundantly available element in the earth's crust and a readily manufacturable material for photovoltaics (PVs). In recent years, several technologies have been developed that promise to take the performance of thin-film silicon PVs well beyond that of the currently established amorphous Si PV technology. Thin-film silicon, like no other thin-film material, is very effective in tandem and triple-junction solar cells. The research and development on thin crystalline silicon on foreign substrates can be divided into two different routes: a low-temperature route compatible with standard float glass or even plastic substrates, and a high-temperature route (>600°C). This article reviews the material properties and technological challenges of the different thin-film silicon PV materials.

Effect of c-Si1-xGex Thickness Grown by LPCVD on the Performance of Thin-Film a-Si/c-Si1-xGex/c-Si Heterojunction Solar Cells

2012 ◽  
Vol 1447 ◽  
Author(s):  
Sabina Abdul Hadi ◽  
Pouya Hashemi ◽  
Nicole DiLello ◽  
Ammar Nayfeh ◽  
Judy L. Hoyt
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Layer Thickness ◽  
Surface Region ◽  
Absorber Layer ◽  
Buffer Layers ◽  
Optical Carrier ◽  
Near Surface ◽  
Heterojunction Solar Cells ◽  
P Type

ABSTRACTIn this paper the effect of Si1-xGex absorber layer thickness on thin film a-Si:H/crystalline-Si1-xGex/c-Si heterojunction solar cells (HIT cells) is studied by simulation and experiment. Cells with 1, 2 and 4 μm-thick epitaxial cap layers of p-type Si0.59Ge0.41 on top of 5 μm Si1-xGex graded buffer layers are fabricated and compared to study the effect of the absorber layer thickness. The results show no change in Voc (0.41V) and that Jsc increases from 17.2 to 18.1 mA/cm2 when the Si0.59Ge0.41 absorber layer thickness is increased from 1 to 4 μm. The effect of thickness on Jsc is also observed for 2 and 4 μm-thick Si and Si0.75Ge0.25 absorber layers. Experiments and simulations show that larger Ge fractions result in a higher magnitude and smaller thickness dependence of Jsc, due to the larger absorption coefficient that increases optical carrier generation in the near surface region for larger Ge contents.

scholarly journals Effect of Surface Roughness on Oxidation Resistance of Stainless Steel AISI 316Ti During Exposure at High Temperature

2020 ◽  
Vol 29 (12) ◽  
pp. 8060-8069
Author(s):  
Wojciech J. Nowak
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Oxidation Resistance ◽  
Surface Preparation ◽  
Surface Region ◽  
Lower Surface ◽  
Near Surface ◽  
Steel Aisi ◽  
Kinetics Of ◽  
Effect Of Surface

AbstractIn the present work, the influence of surface roughness on oxidation kinetics of AISI 316Ti stainless steel and its consequences in term of oxidation resistance were investigated. Namely, the effect of surface roughness on oxidation resistance was evaluated during different types of cyclic oxidation tests at 900 and 1000 °C. The obtained results revealed that alloy possessing higher surface roughness showed longer lifetime compared to that with lower surface roughness. It was also found that more severe cyclic conditions suppressed the positive effect of surface roughness on sample’s lifetime. The better oxidation resistance of rougher alloy was correlated with suppressed formation of Fe-rich nodules on ground surfaces and explained by the combined effect of introduced defects in the near-surface region and possible increase in residual stresses caused by mechanical surface preparation.

Study of Ion Implanted Copper Laser Mirrors by Spectroscopic Ellipsometry

1986 ◽  
Vol 74 ◽  
Author(s):  
P. G. Snyder ◽  
A. Massengale ◽  
K. Memarzadeh ◽  
J. A. Woollam ◽  
D. C. Ingram ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Ion Implantation ◽  
Void Fraction ◽  
Spectroscopic Ellipsometry ◽  
Low Energy ◽  
Near Surface ◽  
Cu Ions ◽  
Microscopic Surface ◽  
Ion Implanted

AbstractImplantation with 400 keV Ag or Cu ions improves the near-surface microstructural quality and reflectance of diamond turned and mechanically polished flat copper laser mirrors. Spectroscopic ellipsometry is sensitive to changes in either the microscopic surface roughness, or in the nearsurface substrate void fraction, and both parameters are observed to change upon implantation. Substrate density as a function of ion fluence peaks at about 5 × 10 15cm-2. Low energy (300 eV) Ar ion implantation can cause either a reduction or increase in microscopic surface roughness, depending on fluence.

Modulated surface-textured substrates with high haze for thin-film silicon solar cells

2011 ◽  
Vol 1321 ◽  
Author(s):  
O. Isabella ◽  
P. Liu ◽  
B. Bolman ◽  
J. Krč ◽  
M. Zeman
Keyword(s):  
Thin Film ◽  
Surface Roughness ◽  
Zinc Oxide ◽  
Solar Cells ◽  
Sacrificial Layer ◽  
Flat Glass ◽  
Silicon Solar Cells ◽  
Glass Substrates ◽  
Thin Film Silicon ◽  
Surface Modulation

ABSTRACTModulated surface-textured substrates for thin-film silicon solar cells exhibiting high haze in a broad range of wavelengths were fabricated. Glass substrates coated with different thicknesses of a sacrificial layer were wet-etched allowing the manipulation of the surface morphology with surface roughness ranging from 200 nm up to 1000 nm. Subsequently, zinc-oxide layers were sputtered and then wet-etched constituting the final modulated textures. The morphological analysis of the substrates demonstrated the surface modulation, and the optical analysis revealed broad angle intensity distributions and high hazes. A small anti-reflective effect with respect to untreated glass was found for etched glass samples. The performance of solar cells on high-haze substrates was evaluated. The solar cells outperformed the reference cell fabricated on a randomly-textured zinc-oxide-coated flat glass. The trend in the efficiency resembled the increased surface roughness and the anti-reflective effect was confirmed also in solar cell devices.

Study on the Surface and Subsurface Integrity of Ground Monocrystalline Silicon Wafers

2005 ◽  
Vol 291-292 ◽  
pp. 425-432 ◽  
Author(s):  
Ren Ke Kang ◽  
Y.X. Zhang ◽  
Dong Ming Guo ◽  
Zhu Ji Jin
Keyword(s):  
Surface Roughness ◽  
Phase Transformations ◽  
Surface Region ◽  
Silicon Wafers ◽  
Grit Size ◽  
Rhombohedral Structure ◽  
Grinding Wheel ◽  
Subsurface Crack ◽  
Near Surface ◽  
Grinding Conditions

Wafer rotation grinding, as an important processing technology, is widely used in manufacturing and back thinning of the silicon wafer. However, the surface/subsurface integrity of the ground wafer, which has important influences on the surface quality and the output of the wafer in subsequent process, is becoming an attention-catching problem. This study is aimed at experimental investigation of the surface/subsurface integrity in wafer rotation grinding. The surface roughness, the subsurface crack configurations, the subsurface damage depth (SSD) and the phase transformations are evaluated by corresponding methods. The results show that the integrity of the ground wafer has a close relationship with the grit size of the grinding wheel. The surface roughness and the SSD increase with increasing of the grit size. The subsurface crack configurations of (100) silicon wafers are complicated. The material removal mechanism is different under different grinding conditions. Ductile grinding is accompanied by the phase transformations of diamond structure silicon (Si-I). The amorphous silicon (α-Si), the Si-XII phase (r8-rhombohedral structure) and the Si-III phase (bc8-body-centered cubic structure) exist on the near surface region of the wafer ground by #600 and #2000 grinding wheels.

Modification of a-Si(:H) by Thermally Generated Atomic Hydrogen: A Real Time Spectroscopic Ellipsometry Study of Si Bond Breaking

1992 ◽  
Vol 258 ◽  
Author(s):  
Ilsin An ◽  
Youming Li ◽  
C.R. Wronski ◽  
R.W. Collins
Keyword(s):  
Thin Film ◽  
Real Time ◽  
Spectroscopic Ellipsometry ◽  
Atomic Hydrogen ◽  
Effective Diffusion ◽  
Bond Breaking ◽  
Tungsten Filament ◽  
Near Surface ◽  
Plasma Enhanced Cvd

ABSTRACTWe have applied real time spectroscopie ellipsometry (2.5≤hv≤4.5 eV) to investigate in situ hydrogenation of thin film a-Si:H prepared by plasma-enhanced CVD. When a-Si:H is exposed to atomic H generated by a tungsten filament heated in H2, as many as ∼5×1021 Si-Si bonds/cm3 can be converted to Si-H bonds in the top ∼200 Å of the film. We have determined the spectroscopie characteristics of Si-H bonds from optical to near-uv photon energies through an analysis of the changes in the dielectric function of the near-surface of the film upon hydrogenation. The conversion of Si-Si bonds to Si-H bonds is identified as reaction-limited to a depth of ∼500 Å. We find that a surface oxide a few monolayers in thickness acts as an effective diffusion barrier to H-incorporation.

scholarly journals Spectroscopic ellipsometry characterization of thin-film silicon nitride

1998 ◽  
Vol 313-314 ◽  
pp. 193-197 ◽  
Author(s):  
G.E. Jellison, Jr ◽  
F.A. Modine ◽  
P. Doshi ◽  
A. Rohatgi
Keyword(s):  
Thin Film ◽  
Silicon Nitride ◽  
Spectroscopic Ellipsometry ◽  
Thin Film Silicon
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