Method of forming a ceramic layer having a garnet crystal structure phase and COATED ARTICLE by such process

Disclosed is a method for depositing a coating comprising: - providing a substrate; and- thermal evaporation of a ceramic powder comprising a garnet crystal structure, to form a coating on the substrate, the coating comprising a garnet crystal structure phase. The substrate may advantageously be a portion (1, 2, 3, 6, 5, 7) of a processing chamber for the manufacture of strips (9) of semiconductor.