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. R plane orientation
Polished surface: Substrate surface is EPI polished via a special CMP procedure with Ra < 5 A
1 side polished
Package: Each wafer is packed in 1000 class clean room with 100 grade plastic bag with wafer container
Precaution: R plane sapphire wafer is easy to cleave compared with C plane's. Please handle it with a care