Sapphire substrate is the popular substrates for III-V nitrides, superconductor and magnetic epi film due to less mis-matched lattice and stable chemical and physical properties.
Orientation tolerance: +/-0.5 Deg. C plane orientation
Polished surface: substrate surface is EPI polished via a special CMP procedure with RA < 8 A
Package: Each wafer is packed in 1000 class clean room with 100 grade plastic bag with wafer container