scholarly journals Characterization of Light Emitting Porous Polycrystalline Silicon Films

1996 ◽  
Vol 452 ◽  
Author(s):  
M. C. Poon ◽  
P. G. Han ◽  
J. K. O. Sin ◽  
H. Wong ◽  
P. K. Ko
Keyword(s):  
Photoelectron Spectroscopy ◽  
Polycrystalline Silicon ◽  
Amorphous Materials ◽  
Complex Structure ◽  
Laser Source ◽  
Light Emitting ◽  
Full Wave ◽  
Transmission Electron ◽  
Si Films ◽  
Polycrystalline Silicon Films

AbstractPolycrystalline silicon (poly-Si) thin films (∼700nm) were deposited by LPCVD, doped with 950°C phosphorous diffusion, and rendered porous by anodization and stain etching. From x-ray photoelectron spectroscopy, poly-Si films have atomic concentration of C(ls):0(ls):Si(2p) = 6%:15%:79%. However, porous poly-Si (PPS) films with weak photoluminescence (PL) have C:O:Si of 20%:38%:42%. For PPS films with strong PL, C:O:Si is 11%:38%:51%. From micro-Raman, scattered spectra for 632nm laser source has peak at 735nm and full wave half maximum (FWHM) of 76nm, and is similar to the PL spectra excited by 400nm uv laser source. High resolution transmission electron microscopy (TEM) study shows that PPS film is of complex structure and composes of numerous Si nano-crystals (1∼10nm) surrounded by amorphous materials.

Porous Amorphous Si Formation by the Etching of Single Crystal Si Substrates

1992 ◽  
Vol 259 ◽  
Author(s):  
T. George ◽  
R. P. Vasquez ◽  
S. S. Kim ◽  
R.W. Fathauer ◽  
W. T. Pike
Keyword(s):  
Photoelectron Spectroscopy ◽  
Light Emitting ◽  
X Ray ◽  
Si Substrates ◽  
Transmission Electron ◽  
Spin Resonance ◽  
Amorphous Si ◽  
Si Films ◽  
P Type ◽  
Stain Etching

ABSTRACTThe nature of light-emitting porous Si layers produced by non-anodic stain etching of p-type (100) Si substrates is studied. The layers were characterized by transmission electron microscopy as being amorphous in nature. X-ray photoelectron spectroscopy and electron spin resonance measurements show these layers to be composed mainly of a-Si. The formation mechanism of the a-Si is explored using by stain etching SiGe ‘marker’ layers within epitaxially grown Si films and by high temperature annealing. These experiments provide strong evidence for a spontaneous crystalline-amorphous phase transformation during the etching process.

On the Temperature Dependence of Resistivity of Polycrystalline Silicon Films

1987 ◽  
Vol 106 ◽  
Author(s):  
Mark S. Rodder ◽  
Dimitri A. Antoniadis
Keyword(s):  
Numerical Calculation ◽  
Polycrystalline Silicon ◽  
Amorphous Region ◽  
Defect States ◽  
Temperature Dependent ◽  
Step Process ◽  
Dependent Potential ◽  
Si Films ◽  
Polycrystalline Silicon Films ◽  
P Type

ABSTRACTIt is shown that the grain boundary (GB) in polycrystalline-silicon (poly-Si) films need not be modeled as a temperature-dependent potential barrier or as an amorphous region to explain the temperature (T) dependence of resistivity (ρ) in p-type poly-Si films at low T. Specifically, we consider that QB defect states allow for the tunneling component of current to occur by a two-step process. Incorporation of the two-step process in a numerical calculation of ρ vs. T results in excellent agreement with available data from 100 K to 300 K.

Oxidation of silicon carbide and the formation of silica polymorphs

2006 ◽  
Vol 21 (10) ◽  
pp. 2550-2563 ◽  
Author(s):  
Maxime J-F. Guinel ◽  
M. Grant Norton
Keyword(s):  
Silicon Carbide ◽  
Photoelectron Spectroscopy ◽  
Polycrystalline Silicon ◽  
Ambient Pressure ◽  
Silicon Oxycarbide ◽  
Oxide Scales ◽  
X Ray ◽  
Transmission Electron ◽  
Polycrystalline Silicon Carbide ◽  
Crystalline Films

The oxidation of both single crystal and relatively pure polycrystalline silicon carbide, between 973 and 2053 K, resulted in the formation of cristobalite, quartz, or tridymite, which are the stable crystalline polymorphs of silica (SiO2) at ambient pressure. The oxide scales were found to be pure SiO2 with no contamination resulting from the oxidizing environment. The only variable affecting the occurrence of a specific polymorph was the oxidation temperature. Cristobalite was formed at temperatures ≥1673 K, tridymite between 1073 and 1573 K, and quartz formed at 973 K. The polymorphs were determined using electron diffraction in a transmission electron microscope. These results were further confirmed using infrared and Raman spectroscopies. Cristobalite was observed to grow in a spherulitic fashion from amorphous silica. This was not the case for tridymite and quartz, which appeared to grow as oriented crystalline films. The presence of a thin silicon oxycarbide interlayer was detected at the interface between the SiC substrate and the crystalline silica using x-ray photoelectron spectroscopy.

Afm/Tem Investigation of Low Temperature Polycrystalline Silicon Grown by ECR-CVD

1995 ◽  
Vol 406 ◽  
Author(s):  
H. L. Hsiao ◽  
K. C. Wang ◽  
L. W. Cheng ◽  
A. B. Yang ◽  
T. R. Yew ◽  
...  
Keyword(s):  
Low Temperature ◽  
Polycrystalline Silicon ◽  
Electron Cyclotron Resonance ◽  
Film Growth ◽  
Chemical Vapor ◽  
Plan View ◽  
3 Dimensional ◽  
High Resolution Tem ◽  
Si Films ◽  
Polycrystalline Silicon Films

AbstractThe polycrystalline silicon films were deposited by electron cyclotron resonance chemical vapor deposition (ECR-CVD) with hydrogen dilution at 250°C and without any thermal annealing. The surface morphology and the microstructure of the poly-Si films are investigated by atomic force microscopy (AFM), plan-view transmission electron microscopy (TEM), crosssectional TEM and high resolution TEM (HRTEM). The low temperature poly-Si films deposited by ECR-CVD show a special leaf-like grain shape (plan-view) and an upside-down cone shape (3-dimensional view). The grains in the poly-Si films have preferred orientation of <112> and the longer side of the leaf-like grain is direction and the shorter side is direction. Lattice bending and interruption are found in the films. The arrangement of the atoms on the grains are well ordered, while atoms in the interfacial regions are randomly distributed. A simple grain formation model based on growth rate differences between different planes and etching effect can explain the film growth mechanism and the formation of the special grain geometry.

Fast Deposition of Polycrystalline Silicon Films by Hot-Wire CVD

1995 ◽  
Vol 377 ◽  
Author(s):  
A. R. Middya ◽  
A. Lloret ◽  
J. Perrin ◽  
J. Huc ◽  
J. L. Moncel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Polycrystalline Silicon ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Hot Wire ◽  
Crystalline Orientation ◽  
Silicon Thin Films ◽  
Hydrogen Dilution ◽  
Si Films ◽  
Polycrystalline Silicon Films

ABSTRACTPolycrystalline silicon thin films have been deposited at fast growth rates (50 Å/s) by hotwire chemical vapour deposition (HW-CVD) from SiH4/H2 gas mixtures at low substrate temperature (400–500°C). The surface morphology of these films consists of 0.5 – 2.0μm dendritic grains as seen by electron microscopy. The films have a columnar morphology with grains starting from the substrate either on glass or c-Si. Even the 150 nm thick initial layer is polycrystalline. The preferential crystalline orientation of the poly-Si film is apparently not governed by the radiative source but strongly depends on the type and orientation of the substrate. A strong hydrogen dilution (>90%) of silane is essential to obtain poly-Si films with optimal crystalline structure.

Structure of Polycrystalline Silicon Films by Glow-Discharge Decomposition using SiH4/H2/SiF4 at Low Temperature

1999 ◽  
Vol 581 ◽  
Author(s):  
R. Tsuchida ◽  
M. Syed ◽  
T. Inokuma ◽  
Y. Kurata ◽  
S. Hasegawa
Keyword(s):  
Power Supply ◽  
Vapor Deposition ◽  
Local Structure ◽  
Polycrystalline Silicon ◽  
Chemical Vapor ◽  
High Angle Boundary ◽  
Rf Power ◽  
Nanocrystalline Structures ◽  
Si Films ◽  
Polycrystalline Silicon Films

ABSTRACTFor poly-Si films prepared by a plasma-enhanced chemical vapor deposition, we examined the changes in the local structure caused by adding H2 and/or SiF4 in the SiH4 feed gases and by changing supplied rf power values. The conditions of low rf power supply, low H2 addition, and SiF4 addition allow formation of films with microcrystalline or nanocrystalline structures. In addition, the H2 or SiF4 addition was found to be effective in promotive growth of <111> or <110> grains, respectively. In such low crystallized films, it was suggested that high-angle boundary would be formed, leading to a decrease in the density of SiH2 and Si dangling bonds, and to an increase in g values.

Fast High-Density Low-Pressure Plasma Synthesis of GaN Nanocrystals

2005 ◽  
Vol 892 ◽  
Author(s):  
Rebecca Joy Anthony ◽  
Elijah Thimsen ◽  
Joe Johnson ◽  
Stephen A Campbell ◽  
Uwe Kortshagen
Keyword(s):  
Photoelectron Spectroscopy ◽  
Plasma Synthesis ◽  
Light Emitting ◽  
X Ray ◽  
Light Emitting Devices ◽  
Transmission Electron ◽  
Solid State Devices ◽  
Bulk Gan ◽  
Synthesis Routes ◽  
Uv Range

AbstractGallium Nitride is of interest due to its direct bandgap, which allows for efficient emission in the near-UV range. Bulk GaN is already in use in solid-state devices that exploit its emissive properties, however, the promise of GaN nanocrystals as tunable emitters for use in light-emitting devices and lasers has led to the recent exploration of nanocrystalline GaN synthesis routes. Here we discuss the use of nonthermal plasmas for the synthesis of nanocrystalline pow-ders of GaN. The particles were examined using transmission electron microscopy and x-ray photoelectron spectroscopy.

STUDY OF THE MICRO-STRUCTURE OF PtxSi ULTRA-THIN FILM

2011 ◽  
Vol 25 (21) ◽  
pp. 2925-2929 ◽  
Author(s):  
SHUANG LIU ◽  
CHARLES M. FALCO ◽  
ZHIYONG ZHONG
Keyword(s):  
Thin Film ◽  
Photoelectron Spectroscopy ◽  
Xps Analysis ◽  
X Ray Diffraction ◽  
Micro Structure ◽  
X Ray ◽  
Transmission Electron ◽  
Si Films ◽  
Pt Films ◽  
Thin Platinum

Ultra-thin platinum (Pt) films were deposited on Si (100) substrates at 160°C by magnetron sputtering and subsequently annealed to form silicides. The thickness of the Pt x Si films was found to be approximately 4 nm as determined by transmission electron microscopy (TEM). X-ray photoelectron spectroscopy (XPS) analysis shows that these films consist of PtSi and Pt 2 Si phases, and a multi-layer configuration of SiO x/ PtSi/Pt 2 Si/Si was detected by angle-resolved XPS. However, the Pt 3 Si phase was not detected by X-ray diffraction (XRD).

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