Characteristics and Window Thicknesses of Ion Implanted Semiconductor Detectors

A study of the main characteristics of boron ion implanted N-type silicon detectors is presented : a FWHM of 3.1 keV has been obtained at 77°K for 1 MeV conversion electrons. Special emphasis is given to the window thickness of these counters, which is deduced from the pulse height defect observed for low energy protons as compared to γ-rays of the same energy. The variation of the window thickness with the applied bias voltage is studied for different values of the following parameters : starting material resistivity, crystal axis orientation, dose, annealing temperature. These measurements allowed the determination of the implanted impurity distribution profile down to eight or nine orders of magnitude below the maximum of this profile .