Carbon　nanotips　were　grown　from　a　thin　carbon　film　deposited　on　a　silicon　substrate　by　plasma-enhanced　hot　filament　chemical　vapor　deposition　using　CH4,　H-2　and　NH3　as　the　reaction　gases.　The　results　of　micro-Raman　spectrometry　and　atomic　force　microscopy　indicate　that　the　carbon　film　is　amorphous　carbon　and　rough,　and　the　results　characterized　by　scanning　electron　microscopy　show　that　the　formation　of　the　carbon　nanotips　depends　on　ion　bombardment.　During　ion　bombardment,　there　is　deposition　of　the　carbonaccous　ions　as　well　as　sputter-etching　of　the　etching　ions.　The　theory　related　to　ion　deposition　and　sputtering　was　applied　to　establish　the　formation　model　of　the　carbon　nanotips.　(c)　2007　Elsevier　B.V　All　rights　reserved.