International Conference on Solid State Devices and Materials

We demonstrated a significant improvement of GeSn-based pn diode performance by introducing a new surface passivation technique; ALD-GeO2. We realized GeO2 ALD at 200 °C using tetra-ethoxy germanium precursor and ozone oxidant, and fabri-cated mesa-structured p-Ge0.948Sn0.052/n-Ge devices with surface passivation layers of Al2O3 and GeO2 in-terlayer (IL). Thanks to GeO2 IL, reverse saturation current was significantly reduced to ~10−2 A/cm2, which is the smallest value for GeSn pn diodes with Sn content around 5%. We also discussed a possible role of GeO2 IL on the surface current suppression.