Microfabrication of silicon hydrogenated thin targets for multi-MeV laser-driven proton acceleration

An ad hoc microfabrication technique was employed for the optimization of thin hydrogenated silicon membranes for the first experimental application in the field of laser-driven proton acceleration. The tetra methyl ammonium hydroxide wet etching and further microfabrication processes allowed the optimization of the target structure and geometry. Samples were doped in a H ₂ environment during an annealing process at 420 °C in order to increase the hydrogen concentration in the silicon matrix. This solution enabled the production of high-current (about 100 mA at 1 m from the source) and multi-MeV proton beams.