Scanning capacitance microscopy and spectroscopy on SiO2 films with embedded Ge and Si nanoclusters

Scanning capacitance microscopy (SCM) and -spectroscopy (SCS) were applied to study the charge trapping and the charge retention in silicondioxide layers with embedded Ge- or Si-nanoclusters. The nanoclusters were formed by ion beam synthesis. Applying a dc bias to the conductive nano-tip charge injection into the dielectric was achieved. While SCM images visualize the localized trapped charge in the oxide, the locally recorded dC/dV versus V curves allow to quantify the trap density. The evaluation of dCldV shifts was used to compare the electronic properties of different oxide layers in dependence on the implantation parameters. In addition it is demonstrated, that combined SCM/SCS measurements are a suitable tool for the examination of the charge decay as well as of the reliability and degradation of oxide layers on a nanoscale.