Hydrogenated amorphous silicon (a-Si:H) can be produced by plasma-enhanced chemical vapor deposition (PECVD) of SiH4 (silane) mixed with hydrogen. The resulting material shows outstanding radiation hardness properties and can be deposited on a wide variety of substrates. Devices employing a-Si:H technologies have been used to detect many different kinds of radiation, namely, minimum ionizing particles (MIPs), X-rays, neutrons, and ions, as well as low-energy protons and alphas. However, the detection of MIPs using planar a-Si:H diodes has proven difficult due to their unsatisfactory S/N ratio arising from a combination of high leakage current, high capacitance, and limited charge collection efficiency (50% at best for a 30 µm planar diode). To overcome these limitations, the 3D-SiAm collaboration proposes employing a 3D detector geometry. The use of vertical electrodes allows for a small collection distance to be maintained while preserving a large detector thickness for charge generation. The depletion voltage in this configuration can be kept below 400 V with a consequent reduction in the leakage current. In this paper, following a detailed description of the fabrication process, the results of the tests performed on the planar p-i-n structures made with ion implantation of the dopants and with carrier selective contacts are illustrated.
Fabrication of a hydrogenated amorphous silicon detector in 3-d geometry and preliminary test on planar prototypes / Menichelli, M.; Bizzarri, M.; Boscardin, M.; Caprai, M.; Caricato, A. P.; Cirrone, G. A. P.; Crivellari, M.; Cupparo, I.; Cuttone, G.; Dunand, S.; Fano, L.; Ali, O. H.; Ionica, M.; Kanxheri, K.; Large, M.; Maruccio, G.; Monteduro, A. G.; Moscatelli, F.; Morozzi, A.; Papi, A.; Passeri, D.; Petasecca, M.; Rizzato, S.; Rossi, A.; Scorzoni, A.; Servoli, L.; Talamonti, C.; Verzellesi, G.; Wyrsch, N.. - In: INSTRUMENTS. - ISSN 2410-390X. - 5:4(2021), pp. 1-14. [10.3390/instruments5040032]