High rate growth of device grade silicon thin films for solar cells

2001 ◽  
Vol 664 ◽  
Author(s):  
M. Kondo ◽  
S. Suzuki ◽  
Y. Nasuno ◽  
A. Matsuda
Keyword(s):  
Growth Rate ◽  
Solar Cells ◽  
Defect Density ◽  
Chemical Vapor ◽  
High Growth ◽  
Ion Bombardment ◽  
High Rate ◽  
Limiting Factors ◽  
Material Quality ◽  
Deuterium Dilution

ABSTRACTWe have developed a plasma enhanced chemical vapor deposition (PECVD) technique for high-rate growth of µc-Si:H at low temperatures using hydrogen diluted monosilane source gas under high-pressure depletion conditions. It was found that material qualities deteriorate, e.g. crystallinity decreases and defect density increases with increasing growth rate mainly due to ion damage from the plasma. We have found that deuterium dilution improves not only the crystallinity but also defect density as compared to hydrogen dilution and that deuterium to hydrogen ratio incorporated in the film has a good correlation with crystallinity. The advantages of the deuterium dilution are ascribed to lower ion bombardment due to slower ambipolar diffusion of deuterium ion from the plasma. Further improvement of material quality has been achieved using a triode technique where a mesh electrode inserted between cathode and anode electrodes prevents from ion bombardment. In combination with a shower head cathode, the triode technique remarkably improves the crystallinity as well as defect density at a high growth rate. As a consequence, we have succeeded to obtain much better crystallinity and uniformity at 5.8 nm/s with a defect density of 2.6×1016cm−3. We also discuss the limiting factors of growth rate and material quality for µc-Si solar cells.

Control of Materials and Interfaces in μc-Si:H-based Solar Cells Grown at High Rate

2011 ◽  
Vol 1321 ◽  
Author(s):  
Yasushi Sobajima ◽  
Chitose Sada ◽  
Akihisa Matsuda ◽  
Hiroaki Okamoto
Keyword(s):  
Growth Rate ◽  
Solar Cells ◽  
Film Growth ◽  
Defect Density ◽  
Density Measurement ◽  
High Growth ◽  
High Growth Rate ◽  
High Rate ◽  
Bulk Region ◽  
Dangling Bond

ABSTRACTGrowth process of microcrystalline silicon (μc-Si:H) using plasma-enhanced chemicalvapor- deposition method under high-rate-growth condition has been studied for the control of optoelectronic properties in the resulting materials. We have found two important things for the spatial-defect distribution in the resulting μc-Si:H through a precise dangling-bond-density measurement, e. g., (1) dangling-bond defects are uniformly distributed in the bulk region of μc- Si:H films independent of their crystallite size and (2) large number of dangling bonds are located at the surface of μc-Si:H especially when the film is deposited at high growth rate. Starting procedure of film growth has been investigated as an important process to control the dangling-bond-defect density in the bulk region of resulting μc-Si:H through the change in the electron temperature by the presence of particulates produced at the starting period of the plasma. Deposition of Si-compress thin layer on μc-Si:H grown at high rate followed by thermal annealing has been proposed as an effective method to reduce the defect density at the surface of resulting μc-Si:H. Utilizing the starting-procedure-controlling method and the compress-layerdeposition method together with several interface-controlling methods, we have demonstrated the fabrication of high conversion-efficiency (9.27%) substrate-type (n-i-p) μc-Si:H solar cells whose intrinsic μc-Si:H layer is deposited at high growth rate of 2.3 nm/sec.

High Rate Deposition of Microcrystalline Silicon Solar Cells Using 13.56 MHz PECVD – Prerequisites and Limiting Factors

2002 ◽  
Vol 715 ◽  
Author(s):  
Tobias Roschek ◽  
Tobias Repmann ◽  
Oliver Kluth ◽  
Joachim Müller ◽  
Bernd Rech ◽  
...  
Keyword(s):  
Solar Cells ◽  
Plasma Deposition ◽  
Chemical Vapor ◽  
High Rate ◽  
Limiting Factors ◽  
Pulsed Plasma ◽  
Microcrystalline Silicon ◽  
Electrode Distance ◽  
Deposition Parameters ◽  
Wide Range

AbstractMicrocrystalline silicon (μìc-Si:H) solar cells were prepared in a wide range of deposition parameters using high pressure 13.56 MHz plasma-enhanced chemical vapor deposition (PECVD). Focus was on the influence of deposition pressure, electrode distance and the application of a pulsed plasma on high rate deposition of solar cells. At electrode distances between 5 and 20 mm solar cells with efficiencies >8 % were prepared. A medium electrode distance of 10 mm yielded best device performance. Pulsed plasma deposition leads to good results at medium deposition rates of ∼5 Å/s, for higher rates a strong decrease of efficiency was observed. The highest efficiencies in a small area reactor were 8.9 % for CW and 8.4 % for pulsed plasma. We also succeeded in preparing μc-Si:H and a-Si:H/μc-Si:H solar cells in a 30x30 cm2 reactor with efficiencies of 9 % and 12.5 %, respectively.

Development of a Practical High-Rate CVD System

2008 ◽  
Vol 600-603 ◽  
pp. 119-122 ◽  
Author(s):  
Yuuki Ishida ◽  
Tetsuo Takahashi ◽  
Hajime Okumura ◽  
Kazuo Arai ◽  
Sadafumi Yoshida
Keyword(s):  
Growth Rate ◽  
Carrier Concentration ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
High Growth ◽  
High Growth Rate ◽  
High Rate ◽  
Average Growth Rate ◽  
Average Growth ◽  
Process Gases

We have developed a new chemical vapor deposition (CVD) system that is capable of a high growth rate of over 100 µm/h with good uniformities of thickness and carrier concentration. In this CVD system, the process gases contribute efficiently to epitaxial growth. In a demonstration of the abilities of the CVD system, we achieved an average growth rate of 140 µm/h, a thickness uniformity of 3.9%, and a carrier concentration uniformity of 8.9% in a 2-inch wafer, without degradation of the crystallinity.

Guiding Principle to Develop Intrinsic Microcrystalline Silicon Absorber Layer For Solar Cell By Hot-Wire Cvd

2001 ◽  
Vol 664 ◽  
Author(s):  
A. R. Middya ◽  
U. Weber ◽  
C. Mukherjee ◽  
B. Schroeder
Keyword(s):  
Growth Rate ◽  
Solar Cell ◽  
Cell Structure ◽  
Short Circuit ◽  
Chemical Vapor ◽  
High Growth ◽  
High Growth Rate ◽  
Open Circuit ◽  
Hot Wire ◽  
Microcrystalline Silicon

ABSTRACTWe report on ways to develop device quality microcrystalline silicon (μc-Si:H) intrinsic layer with high growth rate by hot-wire chemical vapor deposition (HWCVD). With combine approach of controlling impurities and moderate H-dilution [H2/SiH4 ͌ 2.5], we developed, for the first time, highly photosensitive (103 μc-Si:Hfilms with high growth rate (>1 nm/s); the microstructure of the film is found to be close to amorphous phase (fc ͌ 46 ̻± 5%). The photosensitivity systematically decreases with fc and saturates to 10 for fc> 70%. On application of these materials in non-optimized pin [.proportional]c-Si:H solar cell structure yields 700 mV open-circuit voltage however, surprisingly low fill factor and short circuit current. The importance of reduction of oxygen impurities [O], adequate passivation of grain boundary (GB) as well as presence of inactive GB of (220) orientation to achieve efficient [.proportional]c-Si:H solar cells are discussed.

Homoepitaxial growth and characterization of thick SiC layers with a reduced micropipe density

2004 ◽  
Vol 815 ◽  
Author(s):  
H. Tsuchida ◽  
I. Kamata ◽  
S. Izumi ◽  
T. Tawara ◽  
T. Jikimoto ◽  
...  
Keyword(s):  
Growth Rate ◽  
High Performance ◽  
Defect Density ◽  
Stacking Faults ◽  
High Growth ◽  
High Growth Rate ◽  
Effective Lifetime ◽  
Growth Technique ◽  
Homoepitaxial Growth

AbstractGrowth technique for thick SiC epilayers with a reduced micropipe density has been developed in a vertical hot-wall CVD reactor. Micropipe closing by growing an epilayer is possible with a nearly 100% probability for 4H-SiC substrates oriented (0001) and (000-1) off-cut towards either [11-20] or [1-100]. By applying the micropipe closing technique, a high-performance Schottky barrier diode (SBD) was demonstrated on a substrate including micropipes. Growth of low-doped and thick SiC epilayers is also possible with a good morphology at a high growth rate, and 14.4 kV blocking performance was demonstrated using a 210 μm-thick epilayer. Epitaxial growth on (000-1) substrates with low doping and a low epi-induced defect density was also demonstrated. Deep centers and impurities were investigated to determine the effective lifetime killer of the epilayers. Dislocations and stacking faults in epilayers grown on 4H-SiC substrates off-cut towards different directions were also investigated.

Development of a High Rate 4H-SiC Epitaxial Growth Technique Achieving Large-Area Uniformity

2008 ◽  
Vol 600-603 ◽  
pp. 111-114 ◽  
Author(s):  
Masahiko Ito ◽  
L. Storasta ◽  
Hidekazu Tsuchida
Keyword(s):  
Growth Rate ◽  
Epitaxial Growth ◽  
Free Exciton ◽  
High Growth ◽  
Maximum Growth ◽  
High Growth Rate ◽  
Maximum Growth Rate ◽  
High Rate ◽  
Intrinsic Defect ◽  
Large Area

A vertical hot-wall type epi-reactor that makes it possible to simultaneously achieve both a high rate of epitaxial growth and large-area uniformity at the same time has been developed. A maximum growth rate of 250 µm/h is achieved at 1650 °C. Thickness uniformity of 1.1 % and doping uniformity of 6.7 % for a 65 mm radius area are achieved while maintaining a high growth rate of 79 µm/h. We also succeeded in growing a 280 µm-thick epilayer with excellent surface morphology and long carrier lifetime of ~1 µs on average. The LTPL spectrum shows free exciton peaks as dominant, and few impurity-related or intrinsic defect related peaks are observed. The DLTS measurement for an epilayer grown at 80 µm/h shows low trap concentrations of 1.2×1012 cm-3 for Z1/2 center and 6.3×1011 cm-3 for EH6/7 center, respectively.

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