High Dielectric Constant ZrO2 Films by Atomic Layer Deposition Technique on Germanium Substrates

Germanium has been reconsidered as a potential substitute channel material for high-performance MOSFETs due to its intrinsic high mobilities for both electrons (3900 cm2 s-1V-1) and holes (1900 cm2 s-1V-1). In the present work we have fabricated Pt/Ti metal bilayered ALD-ZrO 2/n-Ge based MOS capacitors. The ZrO2 thin film was deposited on n-Ge (100) substrates by using ZrEMA and oxygen precursors at 300 °C in a PEALD system. The Pt/Ti bilayer metallization was carried out using e-beam evaporation and PMA using a RTA system at 350 °C in the forming gas. The thickness of the ZrO2 gate stack was measured to be 3.61 nm using an ellipsometer. The electrical study was done by analyzing capacitance voltage and current voltage measurements. The flat-band shift was found to be 0.22 V, Qeff was 3.55×1012 cm-2 and Dit was 8.53×1012 cm-2 eV-1. Current voltage characteristics have been analyzed to know the conduction mechanism in fabricated MOS devices.