Comment on “(Ta1−xNbx)2O5 films produced by atomic layer deposition: Temperature dependent dielectric spectroscopy and room-temperature I–V characteristics” [J. Appl. Phys. 90, 4532 (2001)]

Abstract

Experimental results on the I–V characteristics of Ta2O5 and mixed Ta–Nb oxide films at room temperature, reported by Strømme et al. [J. Appl. Phys. 90, 4532 (2001)], are reinterpreted in terms of multiphonon-assisted electron tunneling from traps. Electron-phonon coupling constant and trap depth values are elucidated. Multiphonon-assisted electron tunneling theory eliminates ambiguities in the values of the dielectric constant and other basic parameters deduced from the Poole–Frenkel, Fowler–Nordheim, or Schottky models. Only in the low-field range must the Frenkel emission be taken into account.

Evaluation and Comparison of Novel Precursors for Atomic Layer Deposition of Nb2O5Thin Films

“…Nb 2 O 5 is a wide band gap (3.6 eV) dielectric material with a high index of refraction ( n = 2.4) and permittivity (29 to 200 depending of the crystalline phase). Due to its interesting optoelectronic properties, Nb 2 O 5 has a wide range of applications such as capacitor dielectrics − and as catalyst-supporting oxide materials. − In particular, in dynamic random access memories (DRAMs), where the dielectric should possess permittivity exceeding 40, Nb 2 O 5 has been explored as an alternative to the more widely studied SrTiO 3 and the rutile phase TiO 2 doped with Al. This is because the formation of high permittivity rutile phase of TiO 2 requires matching oxidized ruthenium electrode material which can be a cost issue.…”