what is the difference between silicon & polycrystalline silicon?

Answer 1

Silicon is a basic semiconductor element. Common electronic processing methods can change its conductivity between an insulator and a conductor by doping it with impurities, making it very useful in making integrated circuits, etc. One parameter useful in assessing how well the material will work for circuits is the mobility, which is related to how high the conductivity can be.

Several forms of silicon are used. Crystalline silicon (e.g., silicon wafers) is capable of very high mobility, because the crystalline structure allows charge carriers to go far without obstruction.

Polycrystalline silicon has lots of small domains of crystalline silicon, but the domains are not aligned with their neighboring domains. Mobility is lower because charge carriers are obstructed at the domain boundaries.

Amorphous silicon is even more random, on a tiny scale, and hence has even lower mobility.

Examples of where these are typically used:
Crystalline silicon would be used in integrated circuits such as computer chips. Polycrystalline silicon would be used, for example, when adding and annealing more silicon to integrated circuit wafers, or to transparent substrates such as quartz, such as for small LCDs for projectors. Amorphous silicon is commonly used on larger transparent substrates which cannot be heated as high, such as glass plates, for example to make large LCD panels for laptops or televisions.

The element silicon has many other useful forms, such as silicon dioxide (glass, sand).

Answer 2

Silicon in the purest form is known as intrinsic
This is less useful
Silicon doped with imputity pentavalent or other is known as extrinsic and is more used
Now for chips only p type or ntype is not sufficient
Hence to connect p and n types poly silicon is used
as use of metal wud unite all the electrons amd protons
Were ever required the thickness and the length wud work as resistance and capacitaance as well

Answer 3

Silicon is the basic material used to make computer chips, transistors, silicon diodes and other electronic circuits and switching devices because its atomic structure makes the element an ideal semiconductor.

Polycrystalline silicon or polysilicon or poly-Si or simply poly (in context) is a material consisting of multiple small silicon crystals, and has long been used as the conducting gate material in MOSFET and CMOS processing technologies. For these technologies it is deposited using LPCVD reactors at high temperatures and is usually heavily N or P-doped.

Answer 4

Both poly-crystalline and mono-crystalline solar panels are made from the same material, silicon. However the difference is that the poly-crystalline material is made up of millions or billions of small silicon crystals while the mono-crystalline material is actual just that, one large singe crystal of silicon. Single crystal silicon is more efficient at converting photons to electrons for electricity, the poly-silicon its much less efficient because electrons are captured or generated less efficiently where the crystals of silicon touch. However, even though poly solar panels are not as efficient, they are cheaper to manufacture so they can still be competitive on a $/watt basis. They would just need more area to produce the same amount of electricity as the mono-crystalline panels.

Answer 5

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what is the difference between silicon & polycrystalline silicon?

Answer 6

silicon, as used in integrated circuits, is called single-crystal, i.e., the entire wafer of silicon is a single crystal, and nearly perfect, with less than about 1000 defects cm^2. This requires very careful and controlled growth conditions.

Polysilicon is grown in a variety ways, all resulting in a conglomeration of small, single-crystal chunks. As such, its electrical properties are substantially poorer and is normally used where its end-use only requires a capacitor plate function, or where short wire lengths with minimal resistance needed.

For longer wires in integrated circuits, metals are used, aluminum, gold, and copper.

Answer 7

Hydrogen migration in solid-state crystallized and low-pressure chemical-vapor-deposited (LPCVD) polycrystalline silicon (poly-Si) was investigated by deuterium diffusion experiments. The concentration profiles of deuterium, introduced into the poly-Si samples either from a remote D plasma or from a deuterated amorphous-silicon layer, were measured as a function of time and temperature. At high deuterium concentrations the diffusion was dispersive depending on exposure time. The dispersion is consistent with multiple trapping within a distribution of hopping barriers. The data can be explained by a two-level model used to explain diffusion in hydrogenated amorphous silicon. The energy difference between the transport level and the deuterium chemical potential was found to be about 1.2{endash}1.3 eV. The shallow levels for hydrogen trapping are about 0.5 eV below the transport level, while the deep levels are about 1.5{endash}1.7 eV below. The hydrogen chemical potential{mu}{sub H} decreases as the temperature increases. At lower concentrations,{mu}{sub H} was found to depend markedly on the method used to prepare the poly-Si, a result due in part to the dependence of crystallite size on the deposition process. Clear evidence for deuterium deep traps was found only in the solid-state crystallized material. The LPCVD-grown poly-Si, with columnar grains extending through the film thickness, displayed little evidence of deep trapping, and exhibited enhanced D diffusion. Many concentration profiles in the columnar LPCVD material indicated complex diffusion behavior, perhaps reflecting spatial variations of trap densities, complex formation, and/or multiple transport paths. Many aspects of the diffusion in poly-Si are consistent with diffusion data obtained in amorphous silicon.{

Answer 8

silicon is naturally occured semimetal where as polycrystalline silicon is a manmade polymer.which is formed by the process of polymerization.

Answer 9

What Is Polysilicon

Answer 10

http://en.wikipedia.org/wiki/Silicon for info on silicon
http://en.wikipedia.org/wiki/Polycrystalline_silicon for the polycrystalline silicon