Current conduction mechanisms and breakdown fields of Al_xTi_yO/n‐GaAs(001) metal‐insulator‐semiconductor structures

Abstract

We investigated AlxTiyO/n‐GaAs(001) metal‐insulator‐semiconductor (MIS) structures, in which Alx TiyO thin films as high‐k dielectric were obtained by atomic layer deposition, utilizing alternative supply of Al2O3 and TiO2 precursors. Using X‐ray photoelectron spectroscopy, we obtained atomic composition ratios of Al and Ti in the Alx TiyO thin films. It is shown that the breakdown field of the AlxTiyO increases with increase in the Al composition.Based on temperature‐dependent current density‐voltage (J ‐V) characteristics, we elucidated that dominant conduction mechanisms are thermionic emission, Fowler‐Nordheim tunneling, and Poole‐Frenkel conduction, depending on the composition. From the Poole‐Frenkel current, we estimated dielectric constants of the AlxTiyO, which increase with decrease in the Al composition. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The impact of atomic layer deposited SiO2passivation for high-k Ta1−xZrxO on the InP substrate

“…52 Similar recent findings on nanolaminated Al x Ti y O on the III-V substrate by Ui et al show that upon increasing the barrier height Poole-Frenkel conduction changed to F-N tunneling for Al 2 O 3 . 53 Also Krylov et al clearly observed using X-ray photoemission spectroscopy and time of flight secondary ion mass spectrometry, the higher substrate diffusion process enhances the leakage current and reduces the break down voltage. 21 They have correlated their chemical and electrical analysis with the findings that leakage is enhanced by substrate out-diffusion.…”

Synthesis and characterization of mist chemical vapor deposited aluminum titanium oxide films

“…2) One effective solution for balancing between κ and E G is employing aluminum titanium oxide [(Al 2 O 3 ) 1-x (TiO 2 ) x ] with intermediate properties of Al 2 O 3 (κ ∼ 9, E G ∼ 7 eV) and TiO 2 (κ ∼ 50, E G ∼ 3 eV). As a matter of fact, a high-quality Al 1-x Ti x O y gate insulator deposited by the atomic layer deposition (ALD) method and other vacuum deposition techniques has been used for Si-based, [3][4][5] GaAs-based 6,7) and GaN-based devices. 8,9) One alternative approach to obtain Al 1-x Ti x O y thin films is the mist chemical vapor deposition (mist-CVD) technique, which can deposit various metal-oxide thin films from relative non-toxic and nonpyrophoric aqueous solution under atmospheric pressure.…”