Band structure and electronic characteristics of cubic La2O3 gate dielectrics epitaxially grown on InP substrates

摘要

We first reported the hetero-epitaxial growth with good lattice matching of cubic structure La2C>3 dielectric ultra-thin films on InP substrates by PLD. Epitaxial relationship between the La2C>3 film and InP substrate, namely [001]La2o3||[001]inp and [OniLaaoslltOni^p, and cross-section of the stack without interface layer have been revealed by RHEED and HRTEM. The band offset for La2O3/InP is evaluated to be 1.62 eV for valence band and 2.61 eV for conduction band by XPS. A leakage current of 2 x 10~4 A/cm2 at bias voltage of —1 V and small equivalent oxide thickness of 0.3 nm have been measured on the capacitors with W/La2C>3/InP/Al stack.