Won Sang Lee is currently Director and General Manager of GaN/Diamond Division at RFHIC US Corp., Morrisville, North Carolina. He earned his Ph.D in 1999 from Kwang Woon University in Korea and his Post-doc from University of California at Los Angeles in USA. Since 1991, he joined LG Central Institute of Technology as principal engineer. In 2004, he joined Korea Advanced Nano FAB Center as principal engineer. He has been experienced for bring various III-V compound semiconductor technologies from R&D to production, including GaAs 0.15 um p-HEMT/MMIC, 1 um GaAs HBT/MMIC etc. Since he invented PEC (Photo-Electro Chemical) etching process of GaN/Sapphire MESFET for gate recess etching process on 1997, is currently focused on GaN/SiC HEMT, GaN/Diamond HEMT and GaN/Diamond BAW filter for RF and high power electronics market.