Editing Sputtering (section)

==Etching and chemical sputtering==
Removing atoms by sputtering with an inert gas is called ''[[Ion milling machine|ion milling]]'' or ''ion etching''.

Sputtering can also play a role in [[reactive-ion etching]] (RIE), a plasma process carried out with chemically active ions and radicals, for which the sputtering yield may be enhanced significantly compared to pure physical sputtering. Reactive ions are frequently used in [[secondary ion mass spectrometry]] (SIMS) equipment to enhance the sputter rates. The mechanisms causing the sputtering enhancement are not always well understood, although the case of fluorine etching of Si has been modeled well theoretically.<ref name=Schoolcraft1991>{{cite journal| author= T. A. Schoolcraft and B. J. Garrison, Journal of the American Chemical Society| volume= 113| year=1991| pages= 8221| doi = 10.1021/ja00022a005|title=Initial stages of etching of the silicon Si110 2x1 surface by 3.0-eV normal incident fluorine atoms: a molecular dynamics study|journal=Journal of the American Chemical Society| issue= 22}}</ref>

Sputtering observed to occur below the threshold energy of physical sputtering is also often called chemical sputtering.<ref name="Behrisch1981" /><ref name="Behrisch2007" /> The mechanisms behind such sputtering are not always well understood, and may be hard to distinguish from chemical [[etching]]. At elevated temperatures, chemical sputtering of carbon can be understood to be due to the incoming ions weakening bonds in the sample, which then desorb by thermal activation.<ref name="Küppers1995">{{cite journal| author=J. Küppers|journal= Surface Science Reports|volume= 22 |year=1995|pages=249–321|doi = 10.1016/0167-5729(96)80002-1|title=The hydrogen surface chemistry of carbon as a plasma facing material|bibcode = 1995SurSR..22..249K| issue=7–8 }}</ref> The hydrogen-induced sputtering of carbon-based materials observed at low temperatures has been explained by H ions entering between C-C bonds and thus breaking them, a mechanism dubbed ''swift chemical sputtering''.<ref name=Salonen2001>{{cite journal| author=E. Salonen| journal= Physical Review B| volume= 63|year=2001|pages=195415| doi = 10.1103/PhysRevB.63.195415|title=Swift chemical sputtering of amorphous hydrogenated carbon|bibcode = 2001PhRvB..63s5415S| issue=19 | last2= Nordlund| first2= K.| last3= Keinonen| first3= J.| last4= Wu| first4= C.| s2cid= 67829382|display-authors=etal}}</ref>