Semiconductor substrate, semiconductor component and methods

A method, comprising:

• forming a first opening in a first metallization structure formed on a Group III nitride layer arranged on a first major surface of a base substrate, wherein the base substrate comprises a material other than a Group III nitride and comprises a second metallization structure arranged on a second major surface of the base layer that opposes the first major surface, the second metallization structure comprising an electrically insulating inorganic layer arranged directly on the second major surface, wherein the Group III nitride layer comprises a Group III nitride device and the first metallization structure comprises one or more electrically insulating layers and one or more electrically conductive layers that are coupled to the Group III nitride device;
• increasing the depth of the first opening through the Group III nitride layer and into the base substrate and forming an extended first opening, the extended first opening having a base located in the base substrate;
• forming a mask that covers the extended first opening and that exposes a conductive layer of the first metallization structure in a second opening;
• removing the mask and forming a conductive layer that lines the second opening, the extended first opening and the outer surface of the first metallization structure;
• structuring the conductive layer to form a first portion that is electrically coupled to the base substrate and a second portion that is electrically coupled to the conductive layer of the first metallization structure.