INVESTIGATION OF IMPLANTED GALLIUM DEPTH DISTRIBUTIONS IN ZNSXSE1-X BY EPMA

In the present work EPMA combined with Monte Carlo simulation was appl ied to investigate implanted gallium depth distributions in ZnSxSe1-x layers. The layers of about 1 to 4 mum thickness were grown by MOVPE o n (100)-GaAs substrate. The overlap of the Ga and zinc L X-ray spectra and the low gallium net count rates were overcome by stripping the sp ectra of non implanted layers and by applying appropriate beam current s and counting times. Capabilities and limitations of the EPMA techniq ue as applied to depth profile analysis are demonstrated. Despite the mentioned L interference, the detectability limit of EPMA for 340 keV Ga in ZnSxSe1-x is as low as 10(14) cm-2 . The measured Ga Lalpha inte nsity versus beam energy curves reveal variations of the Ga depth prof iles during annealing. Evaluation of the intensity curves by means of Monte Carlo simulations yields the implanted dose densities and the fi rst two moments of the dept distributions, i.e. the projected range an d its standard deviation. The non-annealed profiles agree well with ex pectations, but after thermal annealing th profiles were significantly shifted towards the surface. Comparison of EPM and SIMS results with the example of a non annealed profile in ZnSe has show good agreement.