Structural Characterization and Crystallization Process of Nanostructured Silicon Thin Films Produced in Low-Pressure Silane Plasma

1998 ◽  
Vol 507 ◽  
Author(s):  
G. Viera ◽  
Proca i Cabarrocas ◽  
J. Costa ◽  
S. Martínez ◽  
E. Bertran
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Structural Characterization ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Two Phase ◽  
Silicon Thin Films ◽  
Nanostructured Silicon ◽  
Wide Range ◽  
Diffraction Patterns

ABSTRACTNanostructured silicon thin films (ns-Si:H), consisting of a two-phase mixture of amorphous and ordered material, were obtained by plasma-enhanced chemical vapor deposition (PECVD) under a wide range of plasma conditions. The key to embedding Si-ordered particles in the amorphous Si matrix was the formation of silicon clusters in the gas phase (diameter < 2nm) under conditions of plasma polymerization, and their incorporation into the growing films. The crystallization induced by thermal annealing in these nanostructured films can be attained faster than in conventional a-Si:H thin films, because the silicon-ordered particles cause a heterogeneous nucleation process in which they act as seeds for crystallization. In this work, we present a detailed structural characterization by using electron and X-ray diffraction patterns and Raman spectroscopy. The crystallization dynamics were studied in-situ by Raman spectroscopy.

Nanostructured Silicon thin films Deposited by PECVD in the Presence of Silicon Nanoparticles

1997 ◽  
Vol 467 ◽  
Author(s):  
G. Viera ◽  
P. Roca i Cabarrocas ◽  
S. Hamma ◽  
S. N. Sharma ◽  
J. Costa ◽  
...  
Keyword(s):  
Thin Films ◽  
Silicon Nanoparticles ◽  
Film Growth ◽  
Electrical Characterization ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Silicon Matrix ◽  
Silicon Thin Films ◽  
Nanostructured Silicon ◽  
Transmission Electron

ABSTRACTNanostructured silicon thin films have been deposited by plasma enhanced chemical vapor deposition at low substrate temperature (100 °C) in the presence of silicon nanoparticles. The nanostructure of the films was revealed by transmission electron microscopy, Raman spectroscopy and X-ray diffraction, which showed ordered silicon domains (1–2 nm) embedded in an amorphous silicon matrix. These ordered domains are due to the particles created in the discharge that contribute to the film growth. One consequence of the incorporation of nanoparticles is the accelerated crystallization of the nanostructured silicon thin films when compared to standard a-Si:H, as shown by the electrical characterization during the annealing.

Microstructure and Thermal Features of a-Si:H and nc-Si:H Thin Films Produced by Rf Sputtering

2006 ◽  
Vol 514-516 ◽  
pp. 23-27
Author(s):  
V. Thaiyalnayaki ◽  
M.Fátima Cerqueira ◽  
Francisco Macedo ◽  
João Alves Ferreira
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Thermal Properties ◽  
Rf Sputtering ◽  
Nanocrystalline Silicon ◽  
Transport Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silicon Thin Films ◽  
Thermal Features

Amorphous and nanocrystalline silicon thin films have been produced by reactive r.f. sputtering and their microstructure, optical and thermal properties were evaluated. A good correlation was found between the microstructure determined by Raman spectroscopy and X- ray diffraction and the thermal transport parameters.

Relating mechanical testing and microstructural features of polysilicon thin films

1999 ◽  
Vol 14 (3) ◽  
pp. 688-697 ◽  
Author(s):  
S. Jayaraman ◽  
R. L. Edwards ◽  
K. J. Hemker
Keyword(s):  
Thin Films ◽  
Elastic Constants ◽  
Crystalline Silicon ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Silicon Thin Films ◽  
Bulge Testing ◽  
Transmission Electron ◽  
Wide Range ◽  
Out Of Plane

Polycrystalline silicon thin films (polysilicon) have been deposited on single crystalline silicon substrates, and square and rectangular windows have been etched into these substrates using standard micromachining techniques. Pressure-displacement curves of the resulting polysilicon membranes have been obtained for these geometries, and this data has been used to determine the elastic constants E and v. The microstructural features of the films have been investigated by transmission electron microscopy (TEM) and x-ray diffraction. The grains were observed to be columnar and were found to have a 〈011〉 out-of-plane texture and a random in-plane grain orientation. A probabilistic model of the texture has been used to calculate the bounds of the elastic constants in the thin films. The results obtained from bulge testing (E = 162 ± 4 GPa and v = 0.20 ± 0.03) fall in the wide range of values previously reported for polysilicon and are in good agreement with the microsample tensile measurements conducted on films deposited in the same run as the present study (168 ± 2 GPa and 0.22 ± 0.01) and the calculated values of the in-plane moduli for 〈1103〉 textured films (E = 163.0–165.5 GPa and v = 0.221–0.239).

Experimental Investigation of Microstructure and Piezoresistive Properties of Phosphorus-Doped Hydrogenated Nanocrystalline Silicon Thin Films Prepared by PECVD

2014 ◽  
Vol 609-610 ◽  
pp. 208-217 ◽  
Author(s):  
Hai Bin Pan ◽  
Jian Ning Ding ◽  
Guang Gui Cheng ◽  
Bao Guo Cao
Keyword(s):  
Thin Films ◽  
Experimental Investigation ◽  
Evaluation System ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Two Phase ◽  
Good Thermal Stability ◽  
Silicon Thin Films ◽  
Phosphorus Doped

This paper presents an experimental investigation of microstructure and piezoresistive properties of phosphorus-doped hydrogenated nanocrystalline silicon (nc-Si:H) thin films. The phosphorus-doped nc-Si:H thin films (5% doping ratio of PH3 to SiH4) were deposited by plasma enhanced chemical vapor deposition (PECVD) technique. The microstructure and surface morphology of the deposited thin films was characterized and analyzed with Raman spectroscopy and atomic force microscopy (AFM), respectively. The piezoresistive properties of the deposited thin films were investigated with a designed four-point bending-based evaluation system. In addition, the influence of temperature on the piezoresistive properties of these thin films was evaluated with the temperature coefficient of resistance (TCR) measurements from room temperature up to 80°C. The experimental results show that phosphorus-doped nc-Si:H thin films prepared by PECVD technique are a two-phase material that constitutes of nanocrystalline silicon and amorphous silicon, and they present a granular structure composed of homogeneously scattered nanoclusters formed by nanocrystalline silicon grains (6nm). Moreover, phosphorus-doped nc-Si:H thin films exhibit negative GF at room temperature and show good thermal stability from room temperature up to 80°C, and the value of GF and TCR is about-31 and-509ppm/°C, respectively. These features could make phosphorus-doped nc-Si:H thin films act as a promising material for piezoresistive-based MEMS sensor.

Crystal Structure of Non-Doped and Sn-Doped α-(GaFe)2O3 Thin Films.

2013 ◽  
Vol 1494 ◽  
pp. 147-152 ◽  
Author(s):  
Kentaro Kaneko ◽  
Kazuaki Akaiwa ◽  
Shizuo Fujita
Keyword(s):  
Thin Films ◽  
Chemical Vapor ◽  
Columnar Structure ◽  
Chemical Vapor Deposition Method ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Sn Doping ◽  
Sapphire Substrates ◽  
Wide Range

ABSTRACTCorundum structured α-(GaFe)2O3 alloy thin films were obtained on c-plane sapphire substrates by the mist chemical vapor deposition method. Wide range of X-ray diffraction 2θ/θ scanning measurements indicated that these crystals were epitaxially grown on c-plane sapphire substrates and these are no other crystal oriented phase. The cross-sectional and plane-view transmission electron microscope images showed the growth along the c-axis of α-(GaFe)2O3 thin films on sapphire substrates, forming joint of columnar structure. The non-doped α-(GaFe)2O3 thin films showed ferromagnetic properties at 300 K, though the origin of ferromagnetism still remained unresolved. In order to enhance the spin-carrier interaction, Sn doped α-(GaFe)2O3 alloy thin films were fabricated on c-plane sapphire substrates. X-ray diffraction 2θ/θ and ω scanning measurement results indicated that the highly-crystalline films were epitaxially grown on substrates in spite of the Sn-doping.

On the nature of the phase transitions of aluminosilicate perrhenate sodalite

2020 ◽  
Vol 235 (6-7) ◽  
pp. 213-223
Author(s):  
Hilke Petersen ◽  
Lars Robben ◽  
Thorsten M. Gesing
Keyword(s):  
Raman Spectroscopy ◽  
Phase Transitions ◽  
Decomposition Temperature ◽  
Second Phase ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Two Phase ◽  
Structure Property Relationships ◽  
Heat Capacity Measurements

AbstractThe temperature-dependent structure-property relationships of the aluminosilicate perrhenate sodalite |Na8(ReO4)2|[AlSiO4]6 (ReO4-SOD) were analysed via powder X-ray diffraction (PXRD), Raman spectroscopy and heat capacity measurements. ReO4-SOD shows two phase transitions in the investigated temperature range (13 K < T < 1480 K). The first one at 218.6(1) K is correlated to the transition of dynamically ordered $P\overline{4}3n$ (> 218.6(1 K) to a statically disordered (<218.6(1) K) SOD template in $P\overline{4}3n$. The loss of the dynamics of the template anion during cooling causes an increase of disorder, indicated by an unusual intensity decrease of the 011-reflection and an increase of the Re-O2 bond length with decreasing temperature. Additionally, Raman spectroscopy shows a distortion of the ReO4 anion. Upon heating the thermal expansion of the sodalite cage originated in the tilt-mechanism causes the second phase transition at 442(1) K resulting in a symmetry-increase from $P\overline{4}3n$ to $Pm\overline{3}n$, the structure with the sodalites full framework expansion. Noteworthy is the high decomposition temperature of 1320(10) K.

INVESTIGATION OF THE Si:H FILMS DEPOSITED NEAR THE TRANSITION REGION FOR APPLICATION IN SOLAR CELLS

2006 ◽  
Vol 20 (27) ◽  
pp. 1739-1747 ◽  
Author(s):  
QINGSONG LEI ◽  
ZHIMENG WU ◽  
XINHUA GENG ◽  
YING ZHAO ◽  
JIANPING XI
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Transition Region ◽  
Chemical Vapor ◽  
Transition Process ◽  
Very High Frequency ◽  
Working Pressure ◽  
Hydrogenated Silicon ◽  
Silicon Thin Films ◽  
Narrow Region

Hydrogenated silicon thin films (Si:H) have been deposited by using very high-frequency plasma-enhanced chemical vapor deposition (VHF PECVD). The structural, electrical and optical properties of the films were characterized. The transition process and the effect of pressure were studied. Results suggest that a narrow region, in which the transition from microcrystalline to amorphous growth takes place, exists in the regime of silane concentration (SC). This region is influenced by the working pressure (P). At lower pressure, the transition region is shifted to higher SC. Microcrystalline silicon (μ c-Si:H ) thin films deposited near transition region was applied as i-layer to the p-i-n solar cells. An efficiency of about 5.30% was obtained.

2D X-ray diffraction and molecular modelling of the crystalline structure of polyesters under uniaxial stress

2021 ◽  
pp. 096739112199822
Author(s):  
Ahmed I Abou-Kandil ◽  
Gerhard Goldbeck
Keyword(s):  
Crystalline Structure ◽  
Molecular Modelling ◽  
Three Dimensional ◽  
Uniaxial Stress ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Modelling Techniques ◽  
Diffraction Patterns

Studying the crystalline structure of uniaxially and biaxially drawn polyesters is of great importance due to their wide range of applications. In this study, we shed some light on the behaviour of PET and PEN under uniaxial stress using experimental and molecular modelling techniques. Comparing experiment with modelling provides insights into polymer crystallisation with extended chains. Experimental x-ray diffraction patterns are reproduced by means of models of chains sliding along the c-axis leading to some loss of three-dimensional order, i.e. moving away from the condition of perfect register of the fully extended chains in triclinic crystals of both PET and PEN. This will help us understand the mechanism of polymer crystallisation under uniaxial stress and the appearance of mesophases in some cases as discussed herein.

Determining the C60 molecular arrangement in thin films by means of X-ray diffraction

2011 ◽  
Vol 44 (5) ◽  
pp. 983-990 ◽  
Author(s):  
Chris Elschner ◽  
Alexandr A. Levin ◽  
Lutz Wilde ◽  
Jörg Grenzer ◽  
Christian Schroer ◽  
...  
Keyword(s):  
Thin Films ◽  
Structural Information ◽  
Grazing Incidence ◽  
Test Material ◽  
C60 Fullerene ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molecular Arrangement ◽  
Diffraction Patterns

The electrical and optical properties of molecular thin films are widely used, for instance in organic electronics, and depend strongly on the molecular arrangement of the organic layers. It is shown here how atomic structural information can be obtained from molecular films without further knowledge of the single-crystal structure. C60 fullerene was chosen as a representative test material. A 250 nm C60 film was investigated by grazing-incidence X-ray diffraction and the data compared with a Bragg–Brentano X-ray diffraction measurement of the corresponding C60 powder. The diffraction patterns of both powder and film were used to calculate the pair distribution function (PDF), which allowed an investigation of the short-range order of the structures. With the help of the PDF, a structure model for the C60 molecular arrangement was determined for both C60 powder and thin film. The results agree very well with a classical whole-pattern fitting approach for the C60 diffraction patterns.

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