SHORT-PULSE PLASMA IMMERSION ION-IMPLANTATION OF OXYGEN INTO SILICON - DETERMINATION OF THE ENERGY-DISTRIBUTION

Plasma immersion ion implantation was used to implant oxygen ions into silicon with applied voltage pulses of 40 kV and 2.5 mu s total lengt h. Positive ions from the plasma, O-2(+) and O+, with a continuous ene rgy distribution between 0 nad 40 keV were implanted with nominal dose s between 2x10(16) and 2x10(17)/cm(2). The resulting oxygen depth prof iles were measured with elastic recoil detection analysis using 13.4 M eV alpha particles. The obtained depth profiles were simulated using a linear superposition of single-energy profiles calculated with TRIM, in order to determine relevant parameters of the accelerated ions. The energy distribution of the incident ions is derived from the results obtained and compared with theoretical models. The agreement found is very good. The plasma is found to be composed of 35(8)% O-2(+) and 65( 8)% O+ ions. An Fe contamination in the plasma is observed using Ruthe rford backscattering. (C) 1997 Elsevier Science S.A.