Ridder's SOLAR BVBA Solar Photovoltaic (PV) System

Polycrystalline Silicon
Polycrystalline silicon (Chunk) is grayish, opaque and shiny crystalline pieces with no odor. This product is used for the casting of Multi-Crystalline silicon ingots and the Czochralski (CZ) pulling of Mono-Crystalline silicon Ingots. Wafers are formed of highly pure, nearly defect-free single crystalline material. One process for forming crystalline wafers is known as Czochralski growth invented by the Polish chemist Jan Czochralski. In this process, a cylindrical ingot of high purity crystalline silicon is formed by pulling a seed crystal from a 'melt'. The ingot is then sliced with an inner diameter diamond coated blade and polished to form wafers
Polysilicon is a key component for integrated circuit and central processing unit manufacturers such as AMD and Intel. At the component level, polysilicon has long been used as the conducting gate material in MOSFET and CMOS processing technologies. For these technologies it is deposited using low-pressure chemical-vapour deposition (LPCVD) reactors at high temperatures and is usually heavily N or P-doped.
More recently, intrinsic and doped polysilicon is being used in large-area electronics as the active and/or doped layers in thin-film transistors. Although it can be deposited by LPCVD, plasma-enhanced chemical vapour deposition (PECVD), or solid-phase crystallization (SPC) of amorphous silicon in certain processing regimes, these processes still require relatively high temperatures of at least 300°C. These temperatures make deposition of polysilicon possible for glass substrates but not for plastic substrates. The deposition of polycrystalline silicon on plastic substrates is motivated by the desire to be able to manufacture digital displays on flexible screens. Therefore, a relatively new technique called laser crystallization has been devised to crystallize a precursor amorphous silicon (a-Si) material on a plastic substrate without melting or damaging the plastic. Short, high-intensity ultraviolet laser pulses are used to heat the deposited a-Si material to above the melting point of silicon, without melting the entire substrate. The molten silicon will then crystallize as it cools. By precisely controlling the temperature gradients, researchers have been able to grow very large grains, of up to hundreds of micrometers in size in the extreme case, although grain sizes of 10 nanometres to 1 micrometre are also common. In order to create devices on polysilicon over large-areas however, a crystal grain size smaller than the device feature size is needed for homogeneity of the devices. Another method to produce poly-Si at low temperatures is metal-induced crystallization where an amorphous-Si thin film can be crystallized at temperatures as low as 150C if annealed while in contact of another metal film such as aluminium, gold, or silver. 
Polysilicon has many applications in VLSI manufacturing. One of its primary uses is as gate electrode material for MOS devices. A polysilicon gate's electrical conductivity may be increased by depositing a metal (such as tungsten) or a metal silicide (such as tungsten silicide) over the gate. Polysilicon may also be employed as a resistor, a conductor, or as an ohmic contact for shallow junctions, with the desired electrical conductivity attained by doping the polysilicon material 
One major difference between polysilicon and a-Si is that the mobility of the charge carriers of the polysilicon can be orders of magnitude larger and the material also shows greater stability under electric field and light-induced stress. This allows more complex, high-speed circuity to be created on the glass substrate along with the a-Si devices, which are still needed for their low-leakage characteristics. When polysilicon and a-Si devices are used in the same process this is called hybrid processing. A complete polysilicon active layer process is also used in some cases where a small pixel size is required, such as in projection displays. 
 
Deposition methods 
 
Polysilicon deposition, or the process of depositing a layer of polycrystalline silicon on a semiconductor wafer, is achieved by pyrolyzing silane (SiH4) at 580 to 650 °C. This pyrolysis process releases hydrogen. 
Polysilicon layers can be deposited using 100% silane at a pressure of 25-130 Pa (0.2 to 1.0 Torr) or with 20-30% silane (diluted in nitrogen) at the same total pressure. Both of these processes can deposit polysilicon on 10-200 wafers per run, at a rate of 10-20 nm/min and with thickness uniformities of ±5%. Critical process variables for polysilicon deposition include temperature, pressure, silane concentration, and dopant concentration. Wafer spacing and load size have been shown to have only minor effects on the deposition process. The rate of polysilicon deposition increases rapidly with temperature, since it follows Arrhenius behavior (deposition rate =A*exp(-qEa/kT)). The activation energy (Ea) for polysilicon deposition is about 1.7 eV. Based on this equation, the rate of polysilicon deposition increases as the deposition temperature increases. There will be a minimum temperature, however, wherein the rate of deposition becomes faster than the rate at which unreacted silane arrives at the surface. Beyond this temperature, the deposition rate can no longer increase with temperature, since it is now being hampered by lack of silane from which the polysilicon will be generated. Such a reaction is then said to be 'mass-transport-limited.' When a polysilicon deposition process becomes mass-transport-limited, the reaction rate becomes dependent primarily on reactant concentration, reactor geometry, and gas flow. 
When the rate at which polysilicon deposition occurs is slower than the rate at which unreacted silane arrives, then it is said to be surface-reaction-limited. A deposition process that is surface-reaction-limited is primarily dependent on reactant concentration and reaction temperature. Deposition processes must be surface-reaction-limited because they result in excellent thickness uniformity and step coverage. A plot of the logarithm of the deposition rate against the reciprocal of the absolute temperature in the surface-reaction-limited region results in a straight line whose slope is equal to -qEa/k. 
At reduced pressure levels for VLSI manufacturing, polysilicon deposition rate below 575 °C is too slow to be practical. Above 650 °C, poor deposition uniformity and excessive roughness will be encountered due to unwanted gas-phase reactions and silane depletion. Pressure can be varied inside a low-pressure reactor either by changing the pumping speed or changing the inlet gas flow into the reactor. If the inlet gas is composed of both silane and nitrogen, the inlet gas flow, and hence the reactor pressure, may be varied either by changing the nitrogen flow at constant silane flow, or changing both the nitrogen and silane flow to change the total gas flow while keeping the gas ratio constant. 
Polysilicon doping, if needed, is also done during the deposition process, usually by adding phosphine, arsine, or diborane. Adding phosphine or arsine results in slower deposition, while adding diborane increases the deposition rate. The deposition thickness uniformity usually degrades when dopants are added during deposition. 
 
Upgraded metallurgical-grade silicon 
 
Upgraded metallurgical-grade (UMG) silicon (also known as UMG Si) solar cell was created to close the efficiency gap between industrial multicrystalline and high-efficiency monocrystalline silicon cell. UMG silicon, which is three orders of magnitude less pure than polysilicon, is being researched and considered as a cost-effective alternative to polysilicon. 
A project is targeting 18-22% efficient cells (upgraded metallurgical silicon could potentially reach efficiencies of only 0.5 percent less than polysilicon), at manufacturing costs of less than $1 per peak watt. 
 
And what is now the best? Poly or Mono? 
 
The latest technology makes that at the moment we can offer you Poly – Panels that have even higher efficiency than Mono – Panels. All depends on used technology and quality of the products. 
Closeup of a polycrystalline cell
showing the fingers of conductor material
 
What RIDDER'S – SOLAR was doing to bring Poly-Crystalline cells to a higher level? 
 
  • A special kind of glass that is covering the cells = more light is going trough this glass and the result is a higher efficiency. Glass is made that the specific wavelength of light as we have in Belgium will make that the energy yield becomes higher. Lots of time people are not thinking quite a lot about the glass that is used. But only this will make a huge difference in efficiency when you compare the different kinds of glass. Problem is that you can not see this with your eyes!
  • Using only the best Silicon with a tight tolerance to scratches and other imperfections and with highest level of purity.
  • Connection from the individual cells to each other by using the most modern techniques.
  • Special rigid frame to avoid cracks in the crystals during transport, handling and installation.
  • Special cooling system to eliminate most heat during hot days.
  • Most up to date assembling from the panels and this by using the best products for intermediate layers and back-foils.
  • Exceptional watertight construction with drain system for condensation.
  • 12 years 90% efficiency and 25 years 80% efficiency
Tests give our products a lifetime up to 40 years
All those things together make that we can offer you a superb Poly-Crystalline PV panel that will serve you years on end and will give you the highest output.
For the moment we can offer you the following panels (this can always change due to technical advantages)
From 5 watt up to 280 watt per PV panel. As those values can change as said here above, it is the best to ask info about the evolution we make to offer you the best. The market is making such an evolution that it is nearly impossible to keep a website up to date. So, ask the info you need.
 
POLY SOLAR PANEL SPECS
Parameter Type Maxpower(W) Dimension(MM) Cell Type Weight(kg) Imp(A) Vmp(V) Isc(A) Voc(V)
RS280P-36 280 1960*990*46 156*156/6*12 22,50 7,65 36,57 8,19 43,77
RS275P-36 275 1960*990*46 156*156/6*12 22,50 7,54 36,43 8,07 43,70
RS270P-36 270 1960*990*46 156*156/6*12 22,50 7,44 36,28 7,96 43,63
RS265P-36 265 1960*990*46 156*156/6*12 22,50 8,53 36,14 9,13 43,56
RS260P-36 260 1960*990*46 156*156/6*12 22,50 7,22 36,00 7,72 43,48
RS255P-36 255 1960*990*46 156*156/6*12 22,50 7,08 36,00 7,57 43,48
RS250P-36 250 1960*990*46 156*156/6*12 22,50 7,05 35,42 7,55 43,41
RS245P-33 245 1800*990*46 156*156/6*11 20,60 7,39 33,13 7,91 39,93
RS240P-33 240 1800*990*46 156*156/6*11 20,60 7,27 33,00 7,78 39,86
RS235P-33 235 1800*990*46 156*156/6*11 20,60 7,12 33,00 7,69 39,86
RS230P-33 230 1800*990*46 156*156/6*11 20,60 7,08 32,47 7,57 39,79
RS225P-30 225 1640*980*40 156*156/6*10 18,60 7,62 29,52 8,15 36,18
RS220P-30 220 1640*980*40 156*156/6*10 18,60 7,30 30,12 7,81 36,30
RS215P-30 215 1640*980*40 156*156/6*10 18,60 7,16 30,00 7,66 36,24
RS210P-30 210 1640*980*40 156*156/6*10 18,60 7,11 29,52 7,61 36,18
RS205P-30 205 1640*980*40 156*156/6*10 18,60 6,94 29,52 7,43 36,18
RS200P-30 200 1640*980*40 156*156/6*10 18,60 6,85 29,16 7,33 36,12
RS195P-30 195 1640*980*40 156*156/6*10 18,60 6,68 29,16 7,15 36,12
RS190P-27 190 1485*980*40 156*156/6*9 17,00 7,15 26,56 7,65 32,56
RS185P-27 185 1485*980*40 156*156/6*9 17,00 6,96 26,56 7,45 32,56
RS180P-27 180 1485*980*40 156*156/6*9 17,00 6,85 26,24 7,33 32,50
RS175P-24 175 1330*980*40 156*156/6*8 16,40 7,29 24,00 7,80 28,99
RS170P-24 170 1330*980*40 156*156/6*8 16,40 7,08 24,00 7,57 28,99
RS165P-24 165 1330*980*40 156*156/6*8 16,40 6,98 23,61 7,47 28,94
RS160P-24 160 1330*980*40 156*156/6*8 16,40 6,86 23,32 7,34 28,89
RS130P-18 130 1485*668*35 156*156/4*9 11,60 7,20 18,00 7,72 21,74
RS120P-18 120 1485*668*35 156*156/4*9 11,60 6,86 17,49 7,34 21,67
RS100P-18 100 1245*668*35 156*130/4*9 11,60 5,71 17,49 6,11 2,67
RS90P-18 90 995*668*35 156*104/4*9 9,00 4,96 18,14 5,30 21,81
RS85P-18 85 995*668*35 156*104/4*9 9,00 4,79 17,71 5,13 21,70
RS80P-18 80 995*668*35 156*104/4*9 9,00 4,57 17,49 4,89 21,67
RS75P-18 75 930*668*35 156*95/4*9 8,20 4,28 17,49 4,58 21,67
RS70P-18 70 760*668*35 156*78/4*9 6,80 3,88 18,00 4,16 21,74
RS65P-18 65 760*668*35 156*78/4*9 6,80 3,61 18,00 3,86 21,74
RS60P-18 60 760*668*35 156*78/4*9 6,80 3,43 17,49 3,67 21,67
RS55P-18 55 710*668*35 156*70/4*9 6,30 3,14 17,49 3,36 21,67
RS50P-18 50 710*668*35 156*68/4*9 6,30 2,91 17,13 3,12 21,63
RS45P-18 45 668*546*35 156*52/4*9 4,30 2,48 18,14 2,65 21,81
RS40P-18 40 668*546*35 156*52/4*9 4,30 2,28 17,49 2,44 21,67
RS35P-18 35 668*500*35 156*45/4*9 4,30 2,00 17,49 2,14 21,67
RS30P-18 30 545*515*28 156*39/3*12 3,90 1,71 17,49 1,83 21,67
RS25P-18 25 515*470*28 156*32/3*12 3,90 1,42 17,49 1,52 21,67
RS20P-18 20 550*350*28 78*52/4*9 2,60 1,14 17,49 1,22 21,67
RS10P-18 10 350*310*28 78*26/4*9 1,50 0,57 17,49 0,61 21,67
RS5P-18 5 320*200*18 78*13/2*18 0,80 0,28 17,49 0,30 21,67
Typical Poly-Crystalline PV-panel Typical construction for a Poly PV-Panel
Connectors MC3 of MC4 Typical Powercurve from a Poly-Crystalline module
RIDDERS-SOLAR BVBA
Terlicht 45 - 9451 Kerksken - Belgium
Phone: 053-833512 - Fax : 053-840994
 
greenenergy@ridders-solar.com www.ridders-solar.com