DEPTH PROFILING OF POROUS SILICON SURFACE BY MEANS OF HEAVY-ION TOF ERDA

In recent years the properties of porous silicon, especially the photoluminescence have found widespread interest. In order to acquire more information on this unique material we have performed depth profiling of hydrogen, carbon, oxygen, fluorine and silicon. Among these elements, we have observed a tight correlation between the form of the hydrogen profile and the intensity of photoluminescence. The probe beam for the heavy ion TOF ERDA consisted of 13.6 MeV Cl-35 ions accelerated by a small tandem. A time-of-flight spectrometer was adapted to register heavy recoils where the mass was determined by simultaneously measuring the kinetic energy and flight time of each recoiled particle using a surface barrier detector (SBD) and two timing detectors, respectively. In order to measure hydrogen recoils were employed a conventional ERD counter consisting of 6 mum mylar foil and a SBD set at a somewhat larger angle than the TOF.