Optoelectronic devices in the blue spectral region require doped ZnSxSe1−x layers for electrical confinement and optical waveguilding. Since ion implantation is often used to realize heavy doping in thin layers, we implanted gallium ions with different doses and energies into ZnSe and ZnSxSe1−x (x ≤ 0.4) layers, grown by metalorganic vapor phase epitaxy (MOVPE) on GaAs. Rapid thermal annealing was performed after SiO2 capping. For characterization, we used electron probe micro-analysis (EPMA), photoluminescence (PL) at 11 K, Raman spectroscopy, far infrared reflectivity (FIR) and Hall measurements. In ZnSe, the Ga depth profiles remain nearly gaussian after annealing, indicating weak diffusion. PL shows that both the overall intensity and the ratio of excitonic to deep centre emissions are maximum for annealing at 850°C (30 s), implying optimum crystalline quality and maximum carrier concentration. In addition, the conductivity is maximum (10 Ω-1 cm-1). However, FIR reveals a heavily doped layer at the GaAs interface, which is assigned to the annealing-induced Zn diffusion into the substrate. Furthermore, the PL spectra show donor-acceptor pair (DAP) transitions which can be attributed to shallow acceptors due to complexes of Ga and intrinsic defects. With increasing ion dose the free carrier concentration saturates at 4 × 1017 cm-3 probably due to self-compensation caused by zinc vacancies (VZn). For ZnS0.3Se0.7, EPMA measurements show a diffusion of the Ga towards the surface, while S- and Ga-rich surface defects appear during annealing. After implantation the PL spectra show deep level emissions at 2.08 and 2.35 eV, which were assigned to [GaZn − VZn] complexes and to ZnSe. Optimum annealing seems to occur at 850°C for 30 s, resulting in a maximum PL intensity with strong DAP and excitonic contributions. Similar behaviour was observed for ZnS0.4Se0.6. Up to now, due to the diffusion and compensation, the implanted and annealed ternary layers remain semi-insulating.

Calibrated x-ray intensities of arsenic and gallium, implanted with various ion-energies and doses into silicon, were measured over a wide range of electron-beam energies and angles of incidence. For the first time Monte-Carlo (MC) simulation was applied to evaluate the EPMA-data with respect to depth-profiles parameters, particularly at non-normal electron incidence. Accurate agreement between MC-simulated and measured k-ratios was obtained in the whole range of excitation conditions applied. The resulting range parameters determined from the EPMA data agree closely with those obtained by other authors from RBS or NAA but like these they show systematic deviations from theoretical predictions. Actual measurements on samples implanted with 10(14) ions cm-2 clearly prove the limits of detectability for As and Ga in Si to be below this number. Similar sensitivity was found for elements with atomic numbers Z > 10 but for light elements (Z less-than-or-equal-to 10) the limit of detectability is increased by about one order of magnitude. Provided the concentrations are appropriate, EPMA combined with MC-simulation is a promising technique for the accurate quantitative, non-destructive, and spacially resolved analysis of depth-profiles.