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The irradiation of silicon with ion beams is an established technique to modify its properties. Protons are used for micromachining applications, in conjunction with porous silicon. Porous silicon does not form in areas irradiated with a given fluence of protons (>10¹⁴ cm⁻²). Our work concentrated on the applicability of masked irradiation of silicon wafers with 1.8 MeV proton beams delivered by the TOP-IMPLART LINAC. In our experiments 1-10 Ω*cm n,p-type silicon wafers were masked and irradiated with protons at fluences between 10¹⁴ and 10¹⁵ protons/cm². Porous silicon did not form in the irradiated areas up to a distance from the surface corresponding to the stopping range (30um). The suppression of porous silicon formation is due to the to the neutralization of dopant impurities by implanted protons that increases the local resistivity. The interest in using RF LINAC for micromachining applications lies in the possibility of deep implantation, that allows the realization of 3D structures for MEMS applications. The use of metal masks with uniform beams, instead of scanned micro- and nano-metric ion probes, increases throughput achievable in industrial processing of wafers., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

A variable energy (3-7 MeV) and pulsed current (0.1 – 100 μA) proton beam has been made available for different applications (radiobiology experiments, detectors development, material studies) in an irradiation facility at ENEA-Frascati based on the 7 MeV injector of the protontherapy linac under realization in the framework of the TOP-IMPLART Project. It is a 425 MHz linear accelerator consisting in a 3 MeV RFQ followed by a DTL up to 7 MeV (PL-7 ACCSYS-HITACHI model) followed by an horizontal and a vertical beam transport line. The latter one is particularly suitable for radiobiology in vitro studies allowing to irradiate besides cell monolayes also cell growing in suspension culture. The paper describes the facility and the recent results of the experimental activity., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany