Fabrication of PIN diode detectors on thinned silicon wafers

Thin substrates are one of the possible choices to provide radiation hard detectors for future high-energy physics experiments. Among the advantages of thin detectors are the low full depletion voltage, even after high particle fluences, the improvement of the tracking precision and momentum resolution and the reduced material budget. framework of the CERN RD50 Collaboration, we have developed p–n diode detectors on membranes obtained by locally thinning the silicon substrate by means of tetra-methyl ammonium hydroxide etching from the wafer backside. Diodes of different shapes and sizes have been fabricated on 57 and 99 μm thick membranes. They have been tested, showing a very low leakage current (<0.4 nA/cm2) and, as expected, a very low depletion voltage (<1 V for the 57 μm membrane). The paper describes the technological approach used for devices fabrication and reports selected results from the electrical characterization.