Study of Surface Passivation of CZ c-Si by PECVD a-Si:H Films; A Comparison Between Quasi-Steady-State and Transient Photoconductance Decay Measurement

2013 ◽  
Vol 1536 ◽  
Author(s):  
Omid Madani Ghahfarokhi ◽  
Karsten von Maydell ◽  
Carsten Agert
Keyword(s):  
Steady State ◽  
Gas Flow ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Chemical Vapor ◽  
Minority Carrier Lifetime ◽  
Hydrogen Gas ◽  
Quasi Steady State ◽  
Effective Lifetime ◽  
Transient Mode

ABSTRACTWe have investigated the passivation of low lifetime non-polished Czochralski (CZ) mono-crystalline silicon (c-Si) wafers by hydrogenated amorphous silicon (a-Si:H), deposited by plasma enhanced chemical vapor deposition (PECVD) technique. The dependence of the effective lifetime (τeff) on the deposition parameters including hydrogen gas flow, power and temperature has been studied. Minority carrier lifetime was measured as deposited and also after an annealing step in both quasi-steady-state (QSS) and transient mode of photoconductance decay. By comparison between τeff measured in each of the aforementioned modes, two distinguishable behaviors could be observed. Moreover, to get further insight into the surface passivation mechanism, we have modeled the recombination at a-Si:H/c-Si interface based on the amphoteric nature of dangling bonds. The results of our modeling show that the discrepancy observed between QSS and transient mode is due to the high recombination rate that exists in the bulk of defective CZ wafer and also partly related to the different thicknesses monitored in each mode. So, by comparison between the injection level dependency of τeff measured in QSS and transient modes, we introduce a valuable technique for the evaluation of c-Si bulk lifetime.

Interdigitated Back Contact Silicon Heterojunction (IBC-SHJ) Solar Cell

2007 ◽  
Vol 989 ◽  
Author(s):  
Meijun Lu ◽  
Stuart Bowden ◽  
Ujjwal Das ◽  
Michael Burrows ◽  
Robert Birkmire
Keyword(s):  
Surface Passivation ◽  
Crystalline Silicon ◽  
Spectral Response ◽  
Chemical Vapor ◽  
Front Surface ◽  
Minority Carrier Lifetime ◽  
Back Contact ◽  
Cell Structures ◽  
Current Voltage ◽  
Low Temperature Processing

AbstractInterdigitated back contact silicon heterojunction (IBC-SHJ) solar cells have been developed. This structure has interdigitated p/n amorphous silicon (a-Si:H) films deposited by plasma enhanced chemical vapor deposition (PECVD) on the backside of crystalline silicon (c-Si) wafers, with light irradiating the front surface. IBC-SHJ cells possess advantages over front junction a-Si:H/c-Si heterojunction cells due to minimized current losses in the illuminating side, and over traditional diffused back-junction cells due to low temperature processing combined with the potential of high voltages for the heterojunction. Current-voltage curves, spectral response and laser beam induced current maps have been used to characterize the IBC-SHJ cells. It was found that the IBC-SHJ cell has non-linear illumination level dependence that correlates with effective minority-carrier lifetime. As the performance of these cells is very sensitive to the quality of passivation on front surface, they are ideally suited as a diagnostic tool for detail characterization of surface passivation. Initial cell structures have achieved independently confirmed cell efficiencies of 11.8% under AM1.5 illumination. Device simulation shows an efficiency of higher than 20% can be expected after optimizing the IBC-SHJ cells.

The SiNx films process research by plasma-enhanced chemical vapor deposition in crystalline silicon solar cells

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744101 ◽  
Author(s):  
Bitao Chen ◽  
Yingke Zhang ◽  
Qiuping Ouyang ◽  
Fei Chen ◽  
Xinghua Zhan ◽  
...  
Keyword(s):  
Thin Film ◽  
Chemical Vapor Deposition ◽  
Solar Cell ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Silicon Solar Cell ◽  
Crystalline Silicon ◽  
Chemical Vapor ◽  
Double Layers ◽  
Crystalline Silicon Solar Cell

SiNx thin film has been widely used in crystalline silicon solar cell production because of the good anti-reflection and passivation effect. We can effectively optimize the cells performance by plasma-enhanced chemical vapor deposition (PECVD) method to change deposition conditions such as temperature, gas flow ratio, etc. In this paper, we deposit a new layer of SiNx thin film on the basis of double-layers process. By changing the process parameters, the compactness of thin films is improved effectively. The NH3passivation technology is augmented in a creative way, which improves the minority carrier lifetime. In sight of this, a significant increase is generated in the photoelectric performance of crystalline silicon solar cell.

scholarly journals Surface passivation and optical characterization of Al2O3/a-SiCx stacks on c-Si substrates

2013 ◽  
Vol 4 ◽  
pp. 726-731 ◽  
Author(s):  
Gema López ◽  
Pablo R Ortega ◽  
Cristóbal Voz ◽  
Isidro Martín ◽  
Mónica Colina ◽  
...  
Keyword(s):  
Wavelength Range ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Surface Recombination ◽  
Chemical Vapor ◽  
Optical Characterization ◽  
Surface Recombination Velocity ◽  
Carrier Injection ◽  
Si Substrates

The aim of this work is to study the surface passivation of aluminum oxide/amorphous silicon carbide (Al2O3/a-SiCx) stacks on both p-type and n-type crystalline silicon (c-Si) substrates as well as the optical characterization of these stacks. Al2O3 films of different thicknesses were deposited by thermal atomic layer deposition (ALD) at 200 °C and were complemented with a layer of a-SiCx deposited by plasma-enhanced chemical vapor deposition (PECVD) to form anti-reflection coating (ARC) stacks with a total thickness of 75 nm. A comparative study has been carried out on polished and randomly textured wafers. We have experimentally determined the optimum thickness of the stack for photovoltaic applications by minimizing the reflection losses over a wide wavelength range (300–1200 nm) without compromising the outstanding passivation properties of the Al2O3 films. The upper limit of the surface recombination velocity (S eff,max) was evaluated at a carrier injection level corresponding to 1-sun illumination, which led to values below 10 cm/s. Reflectance values below 2% were measured on textured samples over the wavelength range of 450–1000 nm.

Improved Passivation of a-Si:H / c-Si Interfaces Through Film Restructuring

2008 ◽  
Vol 1066 ◽  
Author(s):  
Michael Zanoni Burrows ◽  
U. K. Das ◽  
S. Bowden ◽  
S. S. Hegedus ◽  
R. L. Opila ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Silicon Surfaces ◽  
Initial Surface ◽  
Effective Lifetime ◽  
Bonding Structure ◽  
First Time ◽  
Post Deposition

ABSTRACTThe as-deposited passivation quality of amorphous silicon films on crystalline silicon surfaces is dependent on deposition conditions and resulting hydrogen bonding structure. However the initial surface passivation can be significantly improved by low temperature post-deposition anneal. For example an improvement in effective lifetime from 780 μsec as-deposited to 2080 μsec post-anneal is reported in the present work. This work probes the hydrogen bonding environment using monolayer resolution Brewster angle transmission Fourier transform infrared spectroscopy of 100 Å thick films. It is found that there is significant restructuring at the a-Si:H / c-Si interface upon annealing and a gain of mono-hydride bonding at the c-Si surface is detected. Calculations show an additional 3.56 − 4.50 × 1014 cm−2 mono-hydride bonding at c-Si surface due to annealing. The estimation of the surface hydride oscillator strength in transmission mode is reported for the first time to be 7.2 × 10−18 cm on Si (100) surface and 7.5 × 10−18 cm on Si (111).

Characterization of Silicon Oxides Formed by Light-Induced Anodisation for Silicon Solar Cell Surface Passivation

2014 ◽  
Vol 1647 ◽  
Author(s):  
Jie Cui ◽  
Xi Wang ◽  
Robert Opila ◽  
Alison Lennon
Keyword(s):  
Steady State ◽  
Silicon Dioxide ◽  
Photoelectron Spectroscopy ◽  
Surface Passivation ◽  
Thermally Grown Oxide ◽  
Silicon Surfaces ◽  
Quasi Steady State ◽  
Silicon Dioxide Film ◽  
Uniform Drift ◽  
P Type

ABSTRACTIn this paper we report the properties of the anodic silicon dioxide film formed using light-induced anodisation (LIA) method and its potential to be used as surface passivation layer of p-type silicon surfaces of silicon solar cells. The high uniformity of the formed oxide is possibly due to the uniform drift of the positive charge carriers in the silicon to the surface being anodised. The oxide grows at higher rate than that in nitric acid, an oxide layer with thickness of 18 nm can be formed by anodising for 10 min with 15 V bias in 0.5 M sulphuric acid. After annealing in oxygen and then forming gas at 400 °C for 30 min, an average effective carrier lifetime of 120 μs was measured by quasi-steady state photoluminance on 180 μm p-type 3-5 Ohm cm Cz silicon wafers, with a value of 110 μs being measured for the same wafers passivated by a thermally-grown oxide of the same thickness. The properties of the anodic silicon dioxide layers formed by LIA have been characterized by ellipsometry, x-ray photoelectron spectroscopy, quasi-steady state photoluminance and Fourier transform infrared spectroscopy.

High-temperature degradation in plasma-enhanced chemical vapor deposition Al2O3 surface passivation layers on crystalline silicon

2014 ◽  
Vol 116 (5) ◽  
pp. 054507 ◽  
Author(s):  
Saskia Kühnhold ◽  
Pierre Saint-Cast ◽  
Bishal Kafle ◽  
Marc Hofmann ◽  
Francesco Colonna ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
High Temperature ◽  
Vapor Deposition ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Chemical Vapor ◽  
Passivation Layers

scholarly journals Catalyst-Less and Transfer-Less Synthesis of Graphene on Si(100) Using Direct Microwave Plasma Enhanced Chemical Vapor Deposition and Protective Enclosures

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5630
Author(s):  
Rimantas Gudaitis ◽  
Algirdas Lazauskas ◽  
Šarūnas Jankauskas ◽  
Šarūnas Meškinis
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Microwave Plasma ◽  
Lattice Mismatch ◽  
Chemical Vapor ◽  
Hydrogen Gas ◽  
Synthesis Process ◽  
Synthesis Time ◽  
Graphene Layers

In this study, graphene was synthesized on the Si(100) substrates via the use of direct microwave plasma-enhanced chemical vapor deposition (PECVD). Protective enclosures were applied to prevent excessive plasma etching of the growing graphene. The properties of synthesized graphene were investigated using Raman scattering spectroscopy and atomic force microscopy. Synthesis time, methane and hydrogen gas flow ratio, temperature, and plasma power effects were considered. The synthesized graphene exhibited n-type self-doping due to the charge transfer from Si(100). The presence of compressive stress was revealed in the synthesized graphene. It was presumed that induction of thermal stress took place during the synthesis process due to the large lattice mismatch between the growing graphene and the substrate. Importantly, it was demonstrated that continuous horizontal graphene layers can be directly grown on the Si(100) substrates if appropriate configuration of the protective enclosure is used in the microwave PECVD process.

Minority carrier lifetime in silicon wafers from quasi-steady-state photoluminescence

2010 ◽  
Vol 97 (9) ◽  
pp. 092109 ◽  
Author(s):  
J. A. Giesecke ◽  
M. C. Schubert ◽  
D. Walter ◽  
W. Warta
Keyword(s):  
Steady State ◽  
Carrier Lifetime ◽  
Minority Carrier ◽  
Minority Carrier Lifetime ◽  
Silicon Wafers ◽  
Quasi Steady State

Surface Passivation of Crystalline Silicon by a-Si:H Thin Films

2014 ◽  
Vol 936 ◽  
pp. 603-606
Author(s):  
Yin Wang ◽  
Wei Li ◽  
An Ran Guo ◽  
Feng Yu ◽  
Jian He ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Carrier Lifetime ◽  
Surface Passivation ◽  
Minority Carrier ◽  
Crystalline Silicon ◽  
Minority Carrier Lifetime ◽  
Rf Magnetron Sputtering ◽  
Hydrogen Flow Rate ◽  
Hydrogen Flow

Surface passivation of c-Si by a-Si:H thin films has been studied. In this paper, the minority carrier lifetime of 345μs (from 85μs) is obtained at optimal hydrogen flow rate (8.0sccm) by using RF-magnetron sputtering method.

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