Compensation
In most cases many types of impurities will be present in the resultant doped semiconductor. If an equal number of donors and acceptors are present in the semiconductor, the extra core electrons provided by the former will be used to satisfy the broken bonds due to the latter, so that doping produces no free carriers of either type. This phenomenon is known as compensation, and occurs at the p-n junction in the vast majority of semiconductor devices. Partial compensation, where donors outnumber acceptors or vice versa, allows device makers to repeatedly reverse (invert) the type of a given portion of the material by applying successively higher doses of dopants, so-called counterdoping. Most modern semiconductors are made by successive selective counterdoping steps to create the necessary P and N type areas.
Although compensation can be used to increase or decrease the number of donors or acceptors, the electron and hole mobility is always decreased by compensation because mobility is affected by the sum of the donor and acceptor ions.
Read more about this topic: Doping (semiconductor)
Famous quotes containing the word compensation:
“Many old people receive pensions for no other reason, it seems to me, but as a compensation for having lived a long time ago.”
—Henry David Thoreau (1817–1862)
“Senators and presidents have climbed so high with pain enough, not because they think the place specially agreeable, but as an apology for real worth, and to vindicate their manhood in our eyes. This conspicuous chair is their compensation to themselves for being of a poor, cold, hard nature.”
—Ralph Waldo Emerson (1803–1882)
“The only compensation which war offers for its manifold mischiefs, is in the great personal qualities to which it gives scope and occasion.”
—Ralph Waldo Emerson (1803–1882)