Edgeless detectors fabricated by dry etching process

This work is based on an innovative approach to reduce the conventional width of the terminating structure of position sensitive detectors to less than 50 μm, still using standard planar fabrication technology. The objective of this new development is to decouple the electric behaviour of the surface from the sensitive volume within a few tens of micrometers. The main idea of this work is to use a dry etching process to cut the detector as close as possible to the current terminating structure with the only limitation of the photolithography process resolution. The dry etching process offers the advantage of low damage surface if compared to diamond saw cut or laser drilling and the possibility of being part of the standard microelectronics fabrication process. Furthermore, the pattern of the cut lines can be determined by the photolithography step. In this work we present the electrical measurements together with the technique used to reduce the insensitive area of a standard microstrip detector to only 25 μm.