Performance of Large Area Silicon Strip-Sensors for GLAST

Abstract

We report on the performance of silicon strip sensors for GLAST [Gamma-ray Large Area Space Telescope], produced by Hamamatsu Photonics, Japan. The size of the sensors is 89.5 mm x 89.5 mm and they were processed on 6 inch high resistivity wafers. By now, over 1,000 of ultimately 11,500 sensors have been produced and 622 have been investigated in detail. The average leakage current density is only 3.4 nA/cm{sup 2} at 25 C. Such a low leakage current density enables us to screen out a sensor having few strips with high leakage current by looking at the total sensor leakage current, instead of measuring individual strip currents. High breakdown voltage is also achieved. Of 10 sensors investigated for high voltage breakdown, all hold bias voltage up to 500 V without significant increase in the leakage current. The faulty strip rate is about 0.01% of 240 k strips tested.