Although the technology of solid-state integrated circuits (IC) has been continuously and steadily progressing since the 1940s, it was only in the early 1980s that its impact on silicon detectors fabrication became really important. It was in this period that the so-called planar process was successfully applied for the first time, with ion implantation of doped regions to form junctions on silicon substrates by Joseph Kemmer. Kemmer's breakthrough idea also exploited the passivating properties of silicon dioxide to obtain devices with low leakage currents. This was possible, thanks to the substantial reduction of surface currents typical of metal semiconductor (Schottky) junctions, which was the fashionable technology for fabrication of semiconductor sensors at that time [1, 2].