A 250-μm pitch 36-channel silicon photo multiplier array prototype using silicon on insulator technology

Abstract A 6 × 6 silicon photomultiplier (SiPM) array aimed at one-to-one coupling to a finely separated scintillator array was fabricated and characterized. All SiPMs were formed in the bulk substrate layer of a silicon on insulator (SOI) wafer for enabling future SiPMs which consists of 3-D integrated electronics without mechanical bonding. Each channel had a size of 250 × 250 μ m 2 and was arranged for satisfying the counting-rate requirements of over 2 Mcps/mm 2 in energy-resolvable X-ray photon counting computed tomography. To minimize the cost and complexity of the system’s back-end architecture and data acquisition, a novel two-dimensional coordinate readout was designed in anode terminals which contributes to the number of readout wires reduction without the position resolution degradation. As a feasibility study, the basic performance of a prototype analog SiPM array using the commercial SOI process was fabricated and characterized. Several features, such as a fast recovery time under 20 ns and a gain of 1 × 1 0 5 were within requirements to realize photon counting CT.