Etch pits and dislocation in {1012} Czochralski sapphire wafers

The reliability of fused KOH for revealing dislocations in the (1̄012) rhombohedral plane in Czochralski-grown sapphire single crystals was investigated by using x-ray-transmission topography. It was found that the etch pits represent closely the dislocations in the (1̄012) sapphire, although a one-to-one correspondence was not established.