Abstract: The invention relates to a master substrate, a method for making a high density relief structure, and optical discs replicated with the high-density relief structure, the master substrate comprising a substrate layer (10) and a recording stack deposited on the substrate layer, the recording stack comprising:—an information layer (12),—an interface layer (11) sandwiched between said information layer and the substrate , forming marks and spaces representing an encoded data pattern, wherein said recording material is an alloy comprising at least two materials of the group of materials containing Ge, Sb, Te, In, Se, Bi, Ag, Ga, Sn, Pb, As. A very high-density relief structure is achieved.

Abstract: The present invention relates to a recording stack for obtaining a high-density relief structure, comprising: a first recording layer (10) on top of a second recording layer (12), the recording layers being supported by a substrate layer (14), wherein, upon projecting light on the recording layers, a local interaction of the recording layers leads to marks (16) on the basis of a local change of the properties with respect to chemical agents of the recording layers. The present invention further relates to a method of manufacturing a relief structure and a method of producing an optical data carrier.

Abstract: The invention relates to a master substrate, a method for making a high-density relief structure, and optical discs replicated with the high-density relief structure, the master substrate comprising a substrate layer (10) and a recording stack deposited on the substrate layer, the recording stack comprising: a mask layer (12) an interface layer (11) sandwiched between said mask layer and the substrate, said mask layer comprising a recording material for forming marks and spaces representing an encoded data pattern, said forming of marks by thermal decomposition by a focused laser beam and said marks having a different phase than the unrecorded material. A very high-density relief structure is achieved.

Abstract: The present invention relates to a method of writing data on a master substrate (10) for optical recording, the master substrate comprising a recording layer (12) and a substrate layer (14), and the recording layer comprising a phase-change material the phase of which can be transferred from crystalline to amorphous by projecting light on the recording 5 layer, the method comprising the steps of: writing a first amorphous mark (32) from a plurality of amorphous marks on the master substrate by at least one write pulse, and providing a cooling gap before the next amorphous mark (32) will be written.