Crystallographic Orientation Dependent Electrical Characteristics of La2O3 MOS Capacitors

Effect of substrate surface orientation on the properties of La2O3 MOS capacitors was investigated. The dielectric-thickness dependence on VFB indicated that the (110) sample contains smaller amount of fixed charge than the other samples of (100) and (111). The EOT after post-metallization annealing also varied with the orientation: larger value for (111) than the other. The x-ray photoemission spectroscopy revealed that the growth of SiO2-rich silicate phase of low permittivity depends on the orientation and can change EOT. The results suggest that the (110) is preferable for small EOT and adequate VFB value when the interface-state density is significantly reduced.