Carbon　nanotip　arrays　were　prepared　from　carbon　films　deposited　on　silicon　by　plasma-enhanced　hot　filament　chemical　vapor　deposition　using　CH4,　NH3　and　H-2　as　reaction　gases.　The　carbon　films　and　arrays　were　investigated　by　atomic　force　microscopy,　scanning　electron　microscopy　and　micro-Raman　spectrometry.　The　results　indicate　that　the　formation　of　the　carbon　nanotip　arrays　greatly　depends　on　the　etchant　gas　ratio　of　NH3　to　H-2.　The　theory　related　to　plasma　and　sputtering　was　applied　to　explain　the　formation　of　the　carbon　nanotip　arrays　under　different　gas　ratios.　(c)　2006　Elsevier　B.V.　All　rights　reserved.