Composition dependence of band offsets for (LaAlO_(3))_(1-x)(Al_(2)O_(3))_(x) gate dielectrics determined by photoelectron spectroscopy and x-ray absorption spectroscopy

摘要

Electronic structures of (LaAlO_(3))_(1-x)(Al_(2)O_(3))_(x) composite films (x(velence)0, 0.2, 0.33, 0.5, and 1) for large scale integration (LSI) gate dielectrics deposited on p-type Si (100) substrates by a combinatorial pulsed laser deposition method have been analyzed using photoelectron spectroscopy and x-ray absorption spectroscopy. The systematic peak shifts due to chemical shifts were observed for core-level spectra. The conduction-band offset became smaller with increasing ratio of Al_(2)O_(3), while the valence-band offset became larger. This precise determination of the band diagram revealed that LaAlO_(3) (x(velence)0) had the optimum band offset for LSI gate dielectrics.