p-type silicon

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p-type silicon

[′pē ¦tīp ′sil·ə‚kän]
Silicon to which more impurity atoms of acceptor type (with valence of 3, such as boron) than of donor type (with valence of 5, such as phosphorus) have been added, with the result that the hole density exceeds the conduction electron density.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

n-type silicon

The use of n-type and p-type silicon is a foundation concept in the design of transistors. Pure silicon is not conductive. However, it can be made conductive by adding other elements to its crystalline structure, which then become known as "n-type" or "p-type" silicon.

The interaction of n-type and p-type silicon to electric fields and to each other is used to make areas in a transistor change from conductive to non-conductive and vice versa (see crystalline semiconductor). See FET, MOSFET, bipolar transistor and doping.

N-Type (Negative)
N-type silicon is silicon that has been chemically combined (doped) with phosphorus gas to make it conductive. A silicon atom has four electrons in its outer shell and bonds tightly with four surrounding silicon atoms creating a crystal matrix with eight electrons in the outer shells. However, phosphorus has five electrons, and when combined, the fifth electron becomes a "free" electron that moves easily within the crystal when a voltage is applied. Because the charge carriers are electrons, n-type refers to a negative charge.

P-Type (Positive)
In contrast, p-type silicon is silicon doped with boron gas that turns it into a conductive material that readily accepts electrons when voltage is applied. Boron has only three electrons in its outer shell and can bond with only three of the four surrounding silicon atoms. This leaves one silicon atom with a vacant location in its outer shell, called a "hole," that readily accepts an electron. Because the charge carriers are holes, p-type silicon is said to have a positive charge.

N-Type and P-Type
This is a very conceptual illustration of the atomic structure of n-type and p-type silicon. (Image courtesy of TechBites Interactive.)
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References in periodicals archive ?
On the other hand, due to the accumulation of negative charges on the silicon surface, the fixed negative charges repel the electrons moving from the P-type silicon side and simultaneously attract the positive charges, thus reducing the number of electrons and holes.
Figure 2 shows X-ray diffraction patterns of (100)-oriented AlN thin films for different distance between the Al target and substrate on a p-type silicon substrate.
In spite of the definite advantages of n-type silicon, p-type silicon comprises 85% of industrial silicon solar cells.
Single crystalline boron-doped p-type silicon with resistivity of 10 [ohm]-cm was used as the substrate, which was etched with HCl for 5 min before deposition.
Asomoza, "Plasma CVD deposited p-type silicon oxide wide-bandgap material for solar cells," Solar Energy Materials and Solar Cells, vol.
p-type silicon (100) as substrates was cut with the size that is 1.5 cm x 2.0 cm and clean with acetone, methanol, and HF (48% HF: DI water (1: 10)).
Commercially, p-type silicon substrates are used as a common photovoltaic (PV) material and occupy a large majority of the PV market sales.
For the solar cell fabrication, n-type emitter was generated by doping the p-type silicon with phosphorus oxychloride (PO[Cl.sub.3]) diffusion at the temperature 845[degrees]C forming a p-n junction underlying the nanowires.
Wang, "Design optimization of bifacial HIT solar cells on p-type silicon substrates by simulation," Solar Energy Materials and Solar Cells, vol.
The p-type silicon base is around 300 [micro]m thick whereas the n-type emitter is around 100 nm thick.
Plasma-enhanced chemical vapor deposition (PECVD) was used to deposit 10 bilayers (nominal thickness 1.5 nm of each layer) of alternative layer of Si-rich Si[O.sub.2] (SRO) and Si[O.sub.2] on <100> 10 ohm cm p-type silicon wafer.
The full Al-BSF forms a good ohmic contact; however, the rear surface passivation is moderate on p-type silicon substrates [1, 2].