In　order　to　connect　several　independent　LEDs　in　series,　inductively　coupled　plasma　(ICP)　deep　etching　of　GaN　is　required　for　isolation.　The　GaN-based　high-voltage　(HV)　LEDs　with　a　5　μm　deep　isolation　groove　and　an　acceptable　mesa　sidewall　angle　of　79.2°　are　fabricated　and　presented.　The　surface　morphology　and　construction　profile　of　the　etched　groove　are　characterized　by　laser　microscopy　and　scanning　electron　microscopy.　After　contact　metal　formation　and　annealing,　the　electrical　properties　are　evaluated　by　I　-　V　characteristics.　The　trend　of　the　I　-　V　curve　has　good　accordance　with　conventional　LEDs.　The　contact　resistance　of　HV　LEDs　is　also　tested　and　was　reduced　by　4.6　Ω　compared　to　conventional　LEDs,　while　the　output　power　increased　by　5　W.　The　results　show　that　this　technique　can　be　applied　to　practical　fabrication.　©　2012　Chinese　Institute　of　Electronics.