DOUBLE-SIDED FOXFET BIASED MICROSTRIP DETECTORS

The use of the field effect transistor, integrated onto AC-coupled sil icon detectors, as a novel technique for biasing the implanted p+ stri ps [P.P. Allport et al., Nucl. Instr. and Meth. A 310 (1991) 155], was first employed for the OPAL microvertex detector. The detector has pr oved very successful, with ladders of three single-sided detectors sho wing signal/noise of 22:1 with MX5 readout electronics [P.P. Allport e t al., Nucl. Instr. and Meth. A 324 (1993) 34; Nucl. Phys. B (Proc. Su ppl.) 32 (1993) 208]. This technique has been extended to bias also th e n+ strips and p strips on the ohmic side of a double-sided detector [P.P. Allport et al., Nucl. Instr. and Meth. A, to be submitted]. Full -size detectors with orthogonal readout have been fabricated by Micron and tested with MX7 readout on both sides. Both the junction and ohmi c sides of these detectors have similar signal/noise values to those f or single-sided wafers [P.P. Allport et al., Nucl. Instr. and Meth. A, to be submitted]. Test structures have been irradiated with beta part icles to study the radiation hardness of the devices, and probe statio n electrical measurements of the detectors and test structures are pre sented.