Professional GaN Wafer Supplier HMT supply 4 inch (100mm) GaN on Sapphire Substrate. We can provide Un-doped and Si-doped N type with single side polishing. The GaN layer is about 4.5um and sapphire thickness about 650um. We always provide very preferential price to customers. The package of GaN substrate is 25PCS in one cassette. We use international express to ship the GaN wafer to you.