Germanium Drift Detectors: from the Idea to the Device

In order to overcome the energy barrier of 20 keV X-rays, only high-Z materials can provide sufficient detection efficiency and Ge is a natural candidate for drift topologies given the superior properties of carrier transport. On the basis of the established high-quality fabrication capability, times are mature to start a challenging R&D program towards the implementation of Ge drift topologies in a fully planar fabrication process. The planar approach will not only produce a desired and significant jump in spectroscopic performance but will also open the way to the powerful integration of drift and pixelated topologies, leading to optimized detection systems for a wide range of applications with hard X- and gamma rays. The focus of this work is on the technological and design issues in the development of Ge drift detectors in planar technology.