Noise in TOB modules and sensor quality Regina Demina University of Rochester

Module 876 Of the 16 modules tested at UCSB, Observed peculiarity in module testing : Noise on some channels increases with bias voltage. Micro discharge effect (also seen in D0 sensors delivered by Micron)

Module 876 Defects in channels 278 and 279. Not found in sensor probing

Module 876

Module 877 Defect (scratch) in channel 333. Not found in sensor probing

Module 877

Module 878 Defect in channel 377. Not found in sensor probing

Module 878

Module 880 Strip 91 a known pinhole in the first sensor.

Module 880

Module 868 Mid-sensor opens in channels 69-71 in the 1st sensor

Module 868

Module 883 Defect in channel 166. Not found in sensor probing

Module 883 Scratch in channel 316

Module 883

Module 872 Defect in channel 303. Not found in sensor probing

Module 872 Scratch in channel 344. Not found in sensor probing

Module 872

Summary Module # Comments 875 Channel 384 has high noise, but no lithography error present. NOT SEEN IN SENSOR PROBING 874 Found High Istrip channel in 2nd sensor (294) causes noise. Remove 293-295 between sensors and module is good 873 Micro-discharge at channel 14 at 270 V (need to pluck 10-18 to remove cmn). No obvious sensor damage. NOT SEEN IN SENSOR PROBING 872 4 channels with noise increase with HV. 3 have obvious lithographic error. NONE SEEN IN SENSOR PROBING 871 Micro-discharge at channel 181 at 300 V (need to pluck 175-187 to remove cmn). No obvious sensor damage. NOT SEEN IN SENSOR PROBING 870 Good 883 Channel 166 has increasing noise with HV. Has lithographic error (see picture). NOT SEEN IN SENSOR PROBING 882 Good

Summary Module # Comments 881 Micro-discharge at channels 438-440 (need to pull 434-444 to stop high cmn). Channels start discharging at 0V and get worse 869 Micro-discharge at channels 29-30 (need to pull 24-36 to stop high cmn) at 400 V 868 3 mid-sensor opens, lithographic error (see photo). NOT FOUND IN SENSOR PROBING 880 NO PROBLEMS 879 NO PROBLEMS 878 Channel 377 has increasing noise vs bias. Lithographic error found in second sensor (see picture). NOT SEEN IN SENSOR PROBING 877 Channel 334 has slightly higher noise at 550 V. Lithographic error found in first sensor. (See picture.) NOT FOUND IN SENSOR PROBING 876 Channels 278-279 have increasing noise vs. bias voltage. Sensor lithographic error found on both channels (see picture) NOT FOUND IN SENSOR PROBING

Summary Out of 16 modules built 11 show some signs of micro discharge. Total number of noisy strips – 17 Number of strips with high I strip – 1 Number of strips with obvious lithographic error – 8 Opens - 3

Module 875

Module 874

Module 873

Module 871

Module 870

Module 882

Module 881

Module 869

Module 879