Editing MOSFET (section)

===Process variations===
With MOSFETs becoming smaller, the number of atoms in the silicon that produce many of the transistor's properties is becoming fewer, with the result that control of dopant numbers and placement is more erratic. During chip manufacturing, random process variations affect all transistor dimensions: length, width, junction depths, oxide thickness ''etc.'', and become a greater percentage of overall transistor size as the transistor shrinks. The transistor characteristics become less certain, more statistical. The random nature of manufacture means we do not know which particular example MOSFETs actually will end up in a particular instance of the circuit. This uncertainty forces a less optimal design because the design must work for a great variety of possible component MOSFETs. See [[Process variation (semiconductor)|process variation]], [[design for manufacturability]], [[reliability engineering]], and [[statistical process control]].<ref name=Boning>{{ cite book |first1=Michael|last1=Orshansky |first2=Sani |last2=Nassif |first3=Duane |last3=Boning |title=Design for Manufacturability And Statistical Design: A Constructive Approach |date=2007 | publisher=Springer |location=New York |url=https://www.amazon.com/gp/reader/0387309284/ref=sib_dp_pt/002-1766819-0058402#reader-link|isbn=9780387309286 }}</ref>