High Quality Content by WIKIPEDIA articles! The X-FAB Silicon Foundries is a group of semiconductor foundries, with headquarters in Erfurt (X-FAB Semiconductor Foundries AG, is located in the industrial south east area between Melchendorfer and Windischholzhausen). This group specializes in the fabrication of analog and mixed-signal integrated circuits for fabless semiconductor companies (hence the name), as well as MEMS and solutions for high voltage applications.