Effect of indium on phase-change characteristics and local chemical states of In–Ge–Sb–Te alloys

Lee

Physica Rapid Research Ltrs

2009

Section: Introductionmentioning

confidence: 99%

Investigation of electrical characteristics of the In₃Sb₁Te₂ ternary alloy for application in phase‐change memory

Lee

Physica Rapid Research Ltrs

2009

“…The aim, to improve its characteristics for technological applications and also to understand the factors leading to the observed behavior, has sparked an interest into its substituted or doped variants. Previously, properties of several differently doped or substituted GST materials have been investigated both experimentally and theoretically. − In this paper we focus on nitrogen doped GST.…”

Section: Introductionmentioning

confidence: 99%

Nanoscale Phase Separation and Building Blocks of Ge₂Sb₂Te₅N and Ge₂Sb₂Te₅N₂ Thin Films

et al. 2009

The atomic structures of thin films of nitrogen-doped Ge2Sb2Te5 (GST) rapid phase-change memory materials with the general compositions Ge2Sb2Te5N (10% N-GST) and Ge2Sb2Te5N2 (18% N-GST) have been investigated by reverse Monte Carlo refinement based on experimental electron diffraction reduced density functions and density functional theory molecular dynamics simulations. It was found that the nitrogen dopant forms predominantly Ge−N bonds, resulting from nanoscale germanium nitride phase separation during cooling. As in the case of pure GST, the main building blocks of the structure are squares of Ge(Sb)−Te−Sb(Ge)−Te atoms with the contribution from rings containing homopolar Sb−Sb, Te−Te, and Ge−Sb bonds increasing with the nitrogen doping level. These squares are related to the elementary building blocks of the corresponding crystalline structures of the metastable cubic phase of GST. The persistent fragments of the germanium nitride phase are azadigermiridine type N−Ge−Ge−N four-membered rings, with central Ge−Ge bonds. There is an indication from theoretical simulations that two amorphous phases may be present in 18% N-GST, with different bonding types.

Journal of Applied Physics

“…1. 13 In the figure, the BE separations between the peaks of the Ga 3d and Zn 3d orbitals and the In 4d and Zn 3d orbitals are represented by "A" and "B," respectively. 10 ͑Ga 2 O 3 :In 2 O 3 :ZnO=1:1:1͒ for different ion-sputtering conditions.…”

Section: Ga 3dmentioning

confidence: 99%

High-resolution soft x-ray spectroscopic study on amorphous gallium indium zinc oxide thin films

Lee

Kang

Baik

et al. 2010

Articles you may be interested inA thermalization energy analysis of the threshold voltage shift in amorphous indium gallium zinc oxide thin film transistors under simultaneous negative gate bias and illumination Amorphous gallium indium zinc oxide ͑a-GIZO͒ thin films of different compositions ͑Ga 2 O 3 :In 2 O 3 :ZnO=1:1:1,2:2:1,3:2:1,4:2:1͒ on Si substrates were investigated by high-resolution x-ray photoelectron spectroscopy and x-ray absorption spectroscopy ͑XAS͒ using synchrotron radiation. The O 1s, Ga 3d, In 4d, Zn 3d core, and shallow-core levels as well as the valence band maxima and O K-edge XAS were investigated. Each O 1s spectrum could be deconvoluted by a main component ͑O 1 in the text͒ representing the Ga-In-Zn-O quaternary system along with two other higher-binding energy ͑BE͒ components ͑O 2 and O 3 in the text͒. The O 2 +O 3 intensity increased as the Ga 2 O 3 content increased. For the as-prepared samples, the spectral peak separations between the Ga 3d ͑ϳ20 eV͒ and Zn 3d ͑ϳ11 eV͒ orbitals and between the In 4d ͑ϳ18 eV͒ and Zn 3d orbitals became larger, respectively, as the Ga 2 O 3 content increased. For the surface-cleaned samples, this trend was the same but with smaller increases in their separations. The sputter-cleaning effectively reduced the Zn 3d intensity by ϳ30% relative to those of Ga 3d and In 4d. The valence band maximum shifted toward higher BE, up to ϳ0.5 eV for the as-prepared samples and ϳ0.25 eV for the cleaned samples, and the conduction band minimum ͑measured at the O K-edge͒ was measured at photon energies ranging upwards to ϳ0.2 eV as the Ga 2 O 3 content increased, demonstrating that the band gap can be tailored by increasing the Ga 2 O 3 content. The effects of increasing Ga 2 O 3 contents on the local chemical states and the corresponding electrical conduction are discussed in this paper.