Cathodoluminescence depth profiling of Ge-implanted SiO2-layers


Cathodoluminescence depth profiling of Ge-implanted SiO2-layers

Fitiing, H.-J.; Barfels, T.; Schmidt, B.; von Czarnowski, A.

Thermally grown SiO2 layers of thickness d = 500 nm have been implanted by Ge+-ions of energy 350 keV and doses 5x1015 to 5x1016 ions/cm2. Thus Ge profiles with a concentration maximum at the depth of about dm = 240 nm are expected. Afterwards the layers have been investigated partially as implanted and after different thermal annealing up to Ta = 1100 °C for one hour in dry nitrogen.
For investigation of the luminescent center profile cathodoluminescence measurements are used under variation of the primary electron energy Eo = 0.5...30 keV. Applying a constant incident power regime Eo x jo = const the depth profiles of luminescent centers are deduced in comparable magnitude from the electron energy transfer profiles dE/dx.
After thermal annealing, not only the typical violet luminescence (at 400 nm) of the Ge centers is strongly increased but also the luminescent center profile is redistributed in a characteristic manner towards the surface. This process should be described by Ge diffusion processes, precipitation and finally Ge nanocluster formation.

Keywords: Cathodoluminescence; depth profiling; luminescent centers; thermal annealing

  • Solid State Phenomena 78-79 (2001) 119-126

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Publ.-Id: 4885