Nucleation of p-Type Microcrystalline Silicon on Amorphous Silicon for n-i-p Solar Cells Using B(CH3)3 And BF3 Dopant Source Gases

1998 ◽  
Vol 507 ◽  
Author(s):  
Joohyun Koh ◽  
H. Fujiwara ◽  
R. J. Koval ◽  
C. R. Wronski ◽  
R. W. Collins ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Chemical Vapor ◽  
Rf Plasma ◽  
Structural Quality ◽  
Microcrystalline Silicon ◽  
Power Flux ◽  
Deposition Parameters ◽  
Layer Deposition ◽  
P Type ◽  
Dopant Source

ABSTRACTReal time spectroscopic ellipsometry (RTSE) has been applied to identify optimal conditions for the nucleation and growth of 120 Å microcrystalline silicon (μc-Si:H) p-layers by rf plasma-enhanced chemical vapor deposition (PECVD) at 200°C on amorphous silicon (a-Si:H) i-layers in the n-i-p solar cell configuration. Analysis of the RTSE data provide the bulk p-layer dielectric function (2.5-4.3 eV), whose amplitude and shape yield insights into the structural quality and crystallinity of the p-layer. Among the deposition parameters varied include the underlying i-layer surface treatment, the p-layer plasma power flux, and the p-layer dopant source gas and flow ratio. Here we focus on the differences between p-layer deposition using trimethyl boron, B(CH3)3, and boron trifluoride, BF3, source gases. We find significant differences attributed to the differing effects of F and CH3radicals in the plasma on silicon crystallite growth.

LIGHT-INDUCED EXCESS CONDUCTIVITY AND THE ROLE OF ARGON IN THE DEPOSITION OF DOPING-MODULATED AMORPHOUS SILICON SUPERLATTICES.

1985 ◽  
Vol 56 ◽  
Author(s):  
F.-C. Su ◽  
S. Levine ◽  
P. E. Vanier ◽  
F. J. Kampas
Keyword(s):  
Amorphous Silicon ◽  
Amorphous Semiconductor ◽  
Excess Conductivity ◽  
The Novel ◽  
Semiconductor Superlattice ◽  
Deposition Parameters ◽  
Superlattice Structures ◽  
Argon Dilution ◽  
P Type

AbstractAmorphous semiconductor superlattice structures consisting of alternating n-type and p-type doped layers of hydrogenated amorphous silicon (a-Si:H) have been made by silane glow discharge in a single chamber system. These multilayered films show the novel phenomenon of light-induced excess conductivity (LEC) associated with a metastable state having a lifetime of order of days. This report shows that the LEC effect is quite dependent on the specific details of the deposition parameters, namely dilution of the silane with inert gas, substrate temperature and layer thickness. In order to investigate the origin of the LEC effect, argon dilution was used for specific regions of the structure. This experiment shows that the slow states are distributed throughout the layers, and are not concentrated at the interfaces.

Light-Induced Effects on Fluorinated Amorphous and Microcrystalline Silicon Films

1996 ◽  
Vol 420 ◽  
Author(s):  
Hong-Seok Choi ◽  
Keun-Ho Jang ◽  
Jhun-Suk Yoo ◽  
Min-Koo Han
Keyword(s):  
Band Gap ◽  
Vapor Deposition ◽  
Optical Band Gap ◽  
Silicon Film ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Rf Plasma ◽  
Microcrystalline Silicon ◽  
Amorphous Silicon Film ◽  
Hydrogenated Amorphous

AbstractThe fluorinated amorphous and microcrystalline silicon (a,μc-Si:H;F) films have been prepared by rf plasma enhanced chemical vapor deposition (PECVD) with SiH 4 and SiF 4 gas mixtures. The stretching Si-O (1085 cm-1) and SiH2 (2100 cm-1) bands estimated from infrared (IR) spectroscope data have related to the evolution of crystallinity and the optical band gap was shifted by introducing Si-O bonds. The sub-band gap absorption coefficient in a,μc-Si:H;F films was about one order lower than that in hydrogenated amorphous silicon film (a-Si:H). The subband gap absorption in a-Si:H;F film was comparable to that in tic-Si:H;F films. The lightinduced degradation of a,μc-Si:H;F films were also suppressed.

1/f Noise in Mott Variable Range Hopping Conduction in p-type Amorphous Silicon

2015 ◽  
Vol 1770 ◽  
pp. 25-30 ◽  
Author(s):  
V.C. Lopes ◽  
A.J. Syllaios ◽  
D. Whitfield ◽  
K. Shrestha ◽  
C.L. Littler
Keyword(s):  
Electrical Conductivity ◽  
Amorphous Silicon ◽  
Chemical Vapor ◽  
Variable Range Hopping ◽  
Temperature Dependent ◽  
Noise Component ◽  
Variable Range ◽  
Noise Measurements ◽  
P Type ◽  
Hydrogenated Amorphous

ABSTRACTWe report on electrical conductivity and noise measurements made on p-type hydrogenated amorphous silicon (a-Si:H) thin films prepared by Plasma Enhanced Chemical Vapor Deposition (PECVD). The temperature dependent electrical conductivity can be described by the Mott Variable Range Hopping mechanism. The noise at temperatures lower than ∼ 400K is dominated by a 1/f component which follows the Hooge model and correlates with the Mott conductivity. At high temperatures there is an appreciable G-R noise component.

DEVELOPMENT OF HIGHLY CONDUCTIVE BORON-DOPED MICROCRYSTALLINE SILICON FILMS FOR APPLICATION IN SOLAR CELLS

2006 ◽  
Vol 20 (03) ◽  
pp. 303-314 ◽  
Author(s):  
QING-SONG LEI ◽  
ZHI-MENG WU ◽  
JIAN-PING XI ◽  
XIN-HUA GENG ◽  
YING ZHAO ◽  
...  
Keyword(s):  
Solar Cells ◽  
Substrate Temperature ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Silicon Films ◽  
Microcrystalline Silicon ◽  
Very High Frequency ◽  
Boron Doped ◽  
Deposition Processes ◽  
P Type

We have examined the deposition of highly conductive boron-doped microcrystalline silicon (μc- Si:H ) films for application in solar cells. Depositions were conducted in a very high frequency plasma enhanced chemical vapor deposition (VHF PECVD) chamber. In the deposition processes, various substrate temperatures (TS) were applied. Highly conductive p-type microcrystalline silicon films were obtained at substrate temperature lower than 210°C. The factors that affect the conductivity of the films were investigated. Results suggest that the dark conductivity, which was determined by the Hall mobility and carrier concentration, is influenced by the structure. The properties of the films are strongly dependent on the substrate temperature. With TS increasing, the dark conductivity (σd) increases initially; reach the maximum values at certain TS and then decrease. Also, we applied the boron-doped μc- Si:H as p-layers to the solar cells. An efficiency of about 8.5% for a solar cell with μc- Si:H p-layer was obtained.

Pre-Patterned CVD Graphene: Insights on ALD deposition parameters and their influence on Al2O3 and graphene layers

MRS Advances ◽  
2016 ◽  
Vol 1 (20) ◽  
pp. 1401-1409 ◽  
Author(s):  
Gabriela B. Barin ◽  
Antonio G. Souza Filho ◽  
Ledjane S. Barreto ◽  
Jing Kong
Keyword(s):  
Electrical Properties ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Graphene Layers ◽  
Deposition Parameters ◽  
Layer Deposition ◽  
Cvd Growth ◽  
Selective Chemical ◽  
Number Of Cycles

ABSTRACTFabrication of graphene nanostructures it is important for both investigating their intrinsic physical properties and applying them into various functional devices. In this work we present a study on atomic layer deposition (ALD) of Al2O3 to produce patterned graphene through area-selective chemical vapor deposition (CVD) growth. A systematic parametric study was conducted to determine how the number of cycles and the purging time affect the morphology and the electrical properties of both graphene and Al2O3 layers.

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 Hydrogen-Radical Density and Improvement of The Crystalline Volume Fraction of Microcrystalline Silicon Films Prepared by Hot-Wire Assisted Pecvd Method

2000 ◽  
Vol 609 ◽  
Author(s):  
Norimitsu Yoshida ◽  
Takashi Itoh ◽  
Hiroki Inouchi ◽  
Hidekuni Harada ◽  
Katsuhiko Inagaki ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Chemical Vapor ◽  
Rf Plasma ◽  
Hot Wire ◽  
Dilution Ratio ◽  
Microcrystalline Silicon ◽  
Hydrogen Dilution ◽  
Hydrogen Radical ◽  
Hydrogen Radicals ◽  
Hydrogenated Amorphous

ABSTRACTHigher crystalline Si volume fractions in hydrogenated microcrystalline silicon ( µc-Si:H) films have been achieved by the hot-wire assisted plasma enhanced chemical vapor deposition (HWA-PECVD) method compared with those in films by conventional PECVD. µc-Si:H films can also be prepared by HWA-PECVD under typical conditions used for preparing hydrogenated amorphous silicon (a-Si:H) films by PECVD, in which the hydrogen-dilution ratio (H2 / SiH4) is ∼ 10. The hot wire seems to produce hydrogen radicals. As a result, the HWA- PECVD method can control hydrogen-radical densities in the RF plasma, and this method can also control the ratio of hydrogen coverage at the surface of the film.

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