Conduction Mechanisms in SrTiO3 Thin Films on Silicon

Abstract

ABSTRACTNew materials with high dielectric constant are currently being explored to replace silicon dioxide as gate dielectric for device scaling below 0.1 μm. With respect to conventional SiO2, these high permittivity dielectrics provide the required equivalent oxide thickness (EOT) without of further reduction of the insulator physical thickness, which is a key issue to limit gate leakage current and to maintain comparable MOSFET operation and reliability. The present paper presents preliminary results on conduction mechanisms in thin epitaxial SrTiO3 films grown by MBE on Si (100). I-V measurements were performed on Al/STO/Si structures at temperatures ranging from 40 K to 290 K. At temperatures lower than 100 K the conduction mechanism of electrons from gate electrode across the oxide barrier neither Schottky emission nor tunneling. For temperatures higher than 100 K Schottky emission occurs and barrier heights were extracted, showing an approximate linearly increase with temperature. In case of Si/STO interface, a Fowler-Nordheim tunneling mechanism was detected at 40 K and at intermediate fields. The extracted barrier heights are: 0.07 eV at Si/STO interface and from 0.26 eV (130 K) to 0.53 eV (290 K) at Al/STO interface.