A　two-step　removing　GaAs　substrate　technique　by　using　HNO3　solution　is　reported.　In　the　authors＇　experiments,　as　compared　with　other　ratios,　the　etch　rate　of　HNO3:H2O2:H2O=1:6:1　is　faster.　In　addition,　the　etched　surface　by　nitric　acid　solution　has　about　0.15　mu　m　of　surface　smoothness.　The　high　selectivity　of　HNO3:H2O2:H2O=1:4:1　for　GaAs/GaInP　is　demonstrated　with　smooth　morphology　whose　roughness　is　about　4.57　nm.　The　advantages　of　this　technique　are　easy,　repeatable,　and　no　contamination.　It　is　a　very　useful　process　in　the　light-emitting　diode　fabrication.　(C)　2010　American　Vacuum　Society.　[DOI:　10.1116/1.3431082]