The physics programme at the ILC relies heavily on pure and efficient identification of heavy- flavour quarks, requiring pixel vertex detectors with 3–4 μm hit resolution and a material budget of 0.1–0.2% of a radiation length per layer.
Although technology choices are still several years in the future, a number of detector concepts are currently being actively studied. I will discuss these concepts and the associated ongoing R&D programmes, including potential sensor technologies (CMOS, CCD, DepFet etc) as well as mechanical and system issues.