APD arrays and large-area APDs via a new planar process

A fabrication process has been developed which allows the beveled-edge-type of avalanche photodiode (APD) to be made without the need for the artful b evel formation steps. This new process, applicable to both APD arrays and t o discrete detectors, greatly simplifies manufacture and should lead to sig nificant cost reduction for such photodetectors. This is achieved through a simple innovation that allows isolation around the device or array pixel t o be brought into the plane of the surface of the silicon wafer, hence a pl anar process. A description of the new process is presented along with perf ormance data for a variety of APD device and array configurations. APD arra y pixel gains in excess of 10 000 have been measured. Array pixel coinciden ce timing resolution of less than 5 ns has been demonstrated. An energy res olution of 6% for 662 keV gamma-rays using a CsI(T1) scintillator on a plan ar processed large-area APD has been recorded. Discrete APDs with active ar eas up to 13 cm(2) have been operated. (C) 2000 Elsevier Science B.V. All r ights reserved.