Deposition of Amorphous and Microcrystalline Si,C Alloy Thin Films by a Remote Plasma-Enhanced Chemical-Vapor Deposition Process

1991 ◽  
Vol 219 ◽  
Author(s):  
C. Wang ◽  
G. Lucovsky ◽  
R. J. Nemanich
Keyword(s):  
Raman Spectra ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Degree Of Crystallinity ◽  
Microcrystalline Silicon ◽  
Electrical And Optical Properties ◽  
Silicon Carbon ◽  
Infrared Measurements ◽  
Si Films ◽  
The Degree Of Crystallinity

ABSTRACTWe have extended the remote PECVD process to the deposition of intrinsic and doped, amorphous and microcrystalline silicon, carbon alloy films, a-Si,C:H and μc-Si,C, respectively. The electrical and optical properties of a-Si,C:H deposited by remote PECVD are comparable to those of films deposited by the glow discharge or GD process. The degree of crystallinity in the μc-Si,C alloys, as determined from the relative intensities of crystalline and amorphous features in the Raman spectra, is lower than that of μc-Si films deposited under comparable deposition conditions. The Raman spectra indicate that the crystallites in the μc-Si,C alloys are Si, while the infrared measurements establish that the intervening amorphous component is an a-Si,C:H alloy.

¼c Silicon Thin Films Deposited by Remote Plasma Enhanced Chemical Vapor Deposition Process

1990 ◽  
Vol 192 ◽  
Author(s):  
C. Wang ◽  
G. N. Parsons ◽  
S. S. Kim ◽  
E. C. Buehler ◽  
R. J. Nemanich ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Substrate Material ◽  
Degree Of Crystallinity ◽  
Silicon Thin Films ◽  
Hydrogen Dilution ◽  
Type C ◽  
Si Films ◽  
P Type

ABSTRACTIn an earlier study, we deposited ¼c-Si thin films by reactive magnetron sputtering (RMS). Here we extend our studies to the deposition of both undoped and high conductivity N-type and P-type ¼c-Si thin films by a remote PECVD. We show that ¼c-Si films can be deposited by bringing hydrogen, H2, into the source gas mixtures. The H2 could introduced by either upstream in a He/H2 mixture and directly plasma excited, or downstream, and be remotely excited along with the silane, SiH4, feed gas. The degree of crystallinity is shown to depend on the hydrogen dilution, the substrate temperature and the substrate material.

Substrate temperature: A critical parameter for the growth of microcrystalline silicon-carbon alloy thin films at low power

1999 ◽  
Vol 14 (6) ◽  
pp. 2554-2559 ◽  
Author(s):  
Arup Dasgupta ◽  
S. C. Saha ◽  
Swati Ray ◽  
R. Carius
Keyword(s):  
Thin Films ◽  
Low Power ◽  
Substrate Temperature ◽  
Critical Parameter ◽  
Chemical Vapor ◽  
Microcrystalline Silicon ◽  
High Hydrogen ◽  
Deposition Parameters ◽  
Silicon Carbon ◽  
Moderate Power

P-type microcrystalline silicon-carbon alloy thin films have been prepared at low power by employing radio-frequency plasma-enhanced chemical vapor deposition (rf-PECVD) technique; judicious choice of deposition parameters is necessary. Substrate temperature has been observed to be the most critical parameter, while high hydrogen dilution is necessary but not a sufficient condition for obtaining crystallinity in silicon-carbon alloy thin films. Best microcrystallinity at moderate power density (78 mW/cm2) has been obtained at a fairly low substrate temperature (180 °C). The highest conductivity of 5.7 Scm−1 of a boron-doped microcrystalline sample could be achieved. Incorporation of carbon in these films has been confirmed from x-ray photoelectron spectroscopic (XPS) studies. Carbon is, however, incorporated only in the amorphous phase while the crystallites are of silicon only as observed from Raman spectra.

Increase of temperature and crystallinity during electrical switching in microcrystalline silicon

2004 ◽  
Vol 808 ◽  
Author(s):  
Jian Hu ◽  
Paul Stradins ◽  
Howard M. Branz ◽  
Qi Wang ◽  
J.R. Weinberg-Wolf ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Microcrystalline Silicon ◽  
Electrical Measurements ◽  
Current Ramp ◽  
Device Resistance ◽  
Boron Doped ◽  
Current Stressing ◽  
Surface Reflectivity ◽  
Si Films ◽  
A Current

ABSTRACTWe investigate electrical stressing and switching in hydrogenated microcrystalline silicon (mc-Si:H) by thermal, and optical and electrical measurements of Cr/mc-Si:H/metal thin-film structures. Boron-doped microcrystalline Si films of 30-50 nm thick are deposited by hot-wire chemical vapor deposition (HWCVD) on Cr-coated glass at 160°C and contacted with Ag or Al. Switching in devices of size 5 to 30 mm is stimulated by a current-ramp from 10 nA to 50 mA. We find that the voltage across the mc-Si:H devices initially increases logarithmically with current, then saturates at 2∼3 V, and finally drops to a low value of 1 to 1.5 V. This drop indicates a permanent decrease of device resistance to below 1 kW. During current stressing, the surface temperature increases with the bias current, and the surface reflectivity changes. After switching, a small increase in crystalline fraction can be observed by micro-Raman scattering measurements. The observations suggest electrothermal processes which cause changes in microstructure of the mc-Si bulk during current stress.

EFFECTS OF INTERELECTRODE SPACING ON THE PROPERTIES OF MICROCRYSTALLINE SILICON ABSORBER AND SOLAR CELLS

2012 ◽  
Vol 1426 ◽  
pp. 105-110
Author(s):  
Bill Nemeth ◽  
Xiaodan Zhang ◽  
Yanfa Yan ◽  
Qi Wang
Keyword(s):  
Solar Cells ◽  
Growth Parameters ◽  
Short Circuit ◽  
Chemical Vapor ◽  
Short Circuit Current ◽  
Precursor Chemistry ◽  
Short Circuit Current Density ◽  
Microcrystalline Silicon ◽  
Very High Frequency ◽  
Si Films

ABSTRACTWe study the effect of the spacing between electrodes in very high frequency plasma enhanced chemical vapor deposition on the properties of microcrystalline silicon films and their related n-i-psolar cells. We vary the spacing from 0.2 to 1.0 cm to deposit microcrystalline silicon at 67.8 MHz while maintaining other growth parameters. The spacing between the electrodes significantly changes the plasma conditions, which govern film precursor chemistry as well as introduce etching and ion bombardment to the film; thereby, influencing nucleation and growth of the microcrystalline Si films. The resulting films were characterized by UV-Vis spectrometry, atomic force microscopy, X-ray diffraction, and transmission electron microscopy. We found that deposition rate decreases, while surface roughness and short circuit current density increase with smaller spacing.

Optical Properties and Structure of Microcrystalline Silicon

1992 ◽  
Vol 258 ◽  
Author(s):  
Hien V. Nguyen ◽  
Ilsin An ◽  
Youming Li ◽  
C.R. Wronski ◽  
R.W. Collins
Keyword(s):  
Optical Properties ◽  
Vapor Deposition ◽  
Geometric Model ◽  
Chemical Vapor ◽  
Mean Free Path ◽  
Microcrystalline Silicon ◽  
Dominant Effect ◽  
Si Films ◽  
Electron Mean Free Path ◽  
Classical Size

ABSTRACTThe optical properties of thin film microcrystalline silicon (μc-Si:H) prepared by plasma-enhanced chemical vapor deposition (PECVD) have been studied by real time spectroscopie ellipsometry in the nucleation regime as isolated crystalline particles increase in size. A simple geometric model of nucleation allows us to remove the dominant effect of voids and extract the dielectric functions of the crystallites themselves. We find that the results can be understood in terms of a classical size effect whereby limitations on the electron mean free path by scattering at crystallite surfaces control the absorption onset from 2.0 to 3.0 eV. Finally, we describe how well-ordered, continuous 15 Å c-Si films can be prepared on metal substrates.

Influence of Power on the Microstructure and Optical Properties of Microcrystalline Si Films

2014 ◽  
Vol 1016 ◽  
pp. 305-308
Author(s):  
Hua Cheng ◽  
Feng Jiang ◽  
Chang Zheng Ma ◽  
Kuo Jiang
Keyword(s):  
Optical Properties ◽  
Vapor Deposition ◽  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Gaseous Mixture ◽  
Chemical Vapor ◽  
Silicon Films ◽  
Microcrystalline Silicon ◽  
Si Films ◽  
Resonance Plasma

Microcrystalline silicon films were deposited using Ar diluted SiH4 gaseous mixture by electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECR-PECVD). The effects of power on microstrcture and optical properties of microcrystalline silicon films were investigated. The results show that, with the increasing of the power, the crystallinity increased, but the concentration of hydrogen decreased monotonously. Furthermore, the absorption coefficient of the films increased monotonously, and the optical bandgap changed from 1.89eV to 1.75eV with the microwave power ranging from 400 W to 650W.

scholarly journals Structural Characterization of SiF4, SiH4 and H2 Hot-Wire-Grown Microcrystalline Silicon Thin Films with Large Grains

2001 ◽  
Vol 664 ◽  
Author(s):  
J. J. Gutierrez ◽  
C. E. Inglefield ◽  
C. P. An ◽  
M. C. DeLong ◽  
P. C. Taylor ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Vapor Deposition ◽  
Volume Fraction ◽  
Annealing Treatment ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Hot Wire ◽  
Microcrystalline Silicon ◽  
Crystal Volume

ABSTRACTIn this paper, we present a comprehensive study of microcrystalline silicon thin film samples deposited by a novel growth process intended to maximize their grain size and crystal volume fraction. Using Atomic Force Microscopy, Raman spectroscopy, and x ray diffraction the structural properties of these samples were characterized qualitatively and quantitatively. Samples were grown using a Hot-Wire Chemical Vapor Deposition process with or without a post-growth hot-wire annealing treatment. During Hot-Wire Chemical Vapor Deposition, SiF4 is used along with SiH4 and H2 to grow the thin films. After growth, some samples received an annealing treatment with only SiF4 and H2 present. These samples were compared to each other in order to determine the deposition conditions that maximize grain size. Large microcrystalline grains were found to be aggregates of much smaller crystallites whose size is nearly independent of deposition type and post-annealing treatment. Thin films deposited using the deposition process with SiF4 partial flow rate of 2 sccm and post-growth annealing treatment had the largest aggregate grains ∼.5 µm and relatively high crystal volume fraction.

Crystallinity and Optoelectronic Properties of μc-SiC:H

1992 ◽  
Vol 283 ◽  
Author(s):  
F. Demichelis ◽  
G. Crovini ◽  
c. Osenga ◽  
C. F. Pirri ◽  
E. Tresso ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Band Structure ◽  
Carbon Content ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Degree Of Crystallinity ◽  
Optical Transitions ◽  
Structure Model ◽  
The Degree Of Crystallinity ◽  
Band Structure Model

ABSTRACTSamples of μc-Si1-xCx:H with different degree of crystallinity and different carbon content were deposited by Plasma Enhanced Chemical Vapor Deposition and characterized by means of optical, electrical and structural measurements. The correlation between the degree of crystallinity and the mechanism of conductivity and optical transitions in both amorphous and crystalline phases and at the crystalline-amorphous interfaces is reported and discussed in terms of a band structure model.

Temperature Dependence of Structure, Transport and Growth of Microcrystalline Silicon: Does Grain Size Correlate with Transport?

1989 ◽  
Vol 149 ◽  
Author(s):  
C. C. Tsai ◽  
G. B. Anderson ◽  
B. Wacker ◽  
R. Thompson ◽  
C. Doland
Keyword(s):  
Grain Size ◽  
Temperature Dependence ◽  
Chemical Vapor ◽  
Degree Of Crystallinity ◽  
Structural Defects ◽  
Thermal Cvd ◽  
Normal Behavior ◽  
Average Grain Size ◽  
Si Films ◽  
Polycrystalline Silicon Films

ABSTRACTThe temperature dependence of the growth, structure and transport of plasma-deposited microcrystalline and polycrystalline silicon films have been investigated over the temperature range of 50°C to 350°C. While low substrate temperature yields small grain sizes as expected, high temperature also tends to suppress the grain growth, contrary to the normal behavior observed in thermal CVD (chemical vapor deposition) where crystallinity grows with temperature. In fact, the highest temperature of 350°C corresponds to the lowest degree of crystallinity. Furthermore, it is found that, unlike the polycrystalline Si prepared by thermal CVD, the transport properties of the Si films do not necessarily correlate with the grain size or structural defects. While the largest average grain size of 800–1000 Å was obtained at 200°C, the highest Hall mobility and conductivity were obtained near 250°C, which corresponds to a material with smaller grains and an abundance of voids.

Sign in / Sign up

Export Citation Format

Share Document