Publication Date:
2014-12-03
Description:
We are reporting the growth and structural, optical, and dielectric properties of Tb 2 O 3 , a relatively unexplored high-k dielectric material. A pulsed-laser deposition technique was used to grow Tb 2 O 3 thin-films on four different substrates: Si(100), SrTiO 3 (100), LaAlO 3 (100), and MgO(100). High-resolution X-ray diffraction and transmission electron microscopy results confirmed that film growth in an oxygen-rich (10 −1 Torr) environment yields nearly single-crystal C-phase films, while a low-oxygen (10 −6 Torr) environment growth results in the formation of monoclinic polycrystalline B-phase films. Optical transmission measurements showed that the bandgap of Tb 2 O 3 is direct in nature with a value of 2.8 eV and 3.4 eV for the cubic and monoclinic phases, respectively. By measuring the capacitance of test devices, quite high dielectric constants of 13.5 and 24.9 were obtained for the B- and C-phase Tb 2 O 3 films, respectively.
Print ISSN:
0003-6951
Electronic ISSN:
1077-3118
Topics:
Physics
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