Ion-implanted Si pn-junction detectors with ultrathin windows

Nuclear radiation detectors have been fabricated by using ion implantation and the Si planar processing technology. While ion dose and energy were kept constant at values of 5x1014 B/cm2 at 12.5 keV and 2.5x1015 P/cm2 at 30 keV, the annealing temperature has been varied between 500 and 1000degC. The Si p+-n dead layer, or detector window, has been measured as a function of the annealing state by using the technique of tilting the detector surface with respect to an incident α-particle beam. The resulting energy losses of the monoenergetic particle beam have been measured with standard high-resolution nuclear spectrometric techniques. The result is that annealing beyond 800degC is necessary to reduce the window thickness from about 0.2 μm to well below 0.1 μm, the concomitant deterioration in detector current being negligible. (orig.)