Dielectric properties of dysprosium- and scandium-doped hafnium dioxide thin films

Abstract

Dysprosium- and scandium-doped HfO2 films have been deposited by atomic-vapor deposition on SiO2∕Si substrates. Glancing-incidence x-ray diffraction demonstrates that Dy0.10Hf0.90Ox and Sc0.10Hf0.90Ox films show a cubic crystal structure, whereas HfO2 films are monoclinic. The dielectric permittivity increases strongly from 16 for HfO2 to 32 for Dy0.10Hf0.90Ox and Sc0.10Hf0.90Ox. This leads to a reduction of the leakage current in the tunneling regime by up to three orders of magnitude for constant effective oxide thickness. For thick films (≳6nm), it is shown that leakage occurs via the Poole-Frenkel mechanism and that doping HfO2 increases leakage for constant physical oxide thickness.

Study of interfacial reactions and phase stabilization of mixed Sc, Dy, Hf high-k oxides by attenuated total reflectance infrared spectroscopy

“…All the high-k films were grown by AVD (Aixtron Tricent TM reactor) on Si (1 0 0) wafers as described elsewhere [6,9,17,18] Sample preparation for grazing angle attenuated total reflectance Fourier transform infrared measurement consists of cleaving square pieces (2 cm  2 cm to 3 cm  3 cm) from the wafers. GATR-FTIR spectroscopy was carried out by means of a 658 single reflection Ge-ATR (supplied by Harrick), placed in the sample compartment of an FTIR spectrometer (Bruker, Vertex 70).…”

“…The permittivity of the HfO 2 layers studied here was determined to be 16, as published elsewhere [6]. This value can be characteristic either for amorphous or monoclinic HfO 2 .…”

“…Tetragonal and cubic high temperature phases on the other hand show much higher permittivities (k $ 70 and 29 respectively [4]). These phases have been shown to be stabilized by doping HfO 2 with lanthanides [5][6][7][8]. Besides Hf based materials, lanthanide scandates are reported to be promising as high-k dielectrics, due to their high permittivity (>20) and crystallization resistance up to high temperatures, which is explained by silicate formation [6,9,10].…”

Hafnium dioxide as a dielectric for highly-sensitive waveguide-coupled surface plasmon resonance sensors

“…In comparison to the Si 3 N 4 dielectric, [13][14][15][16][17] hafnium dioxide offers several attractive properties. For example, HfO 2 is characterized with 4-6 times higher dielectric constant, optical transparency over much wider range of wavelengths (250-2000 nm), 3 times higher density in the solid state, chemical stability, and very high melting point 2758 0 C. [18][19][20][21][22] The high dielectric constant and good optical transparency over wider wavelength range are useful for high sensitivity waveguide coupled bimetallic (WCBM) sensors working in VIS-IR range. The surface plasmon polaritons are characterized by a wavevector…”

Engineering crystallinity of atomic layer deposited gate stacks containing ultrathin HfO2 and a Ti-based metal gate: Effects of postmetal gate anneal and integration schemes

“…[8][9][10][11][12][13][14][15] Various doping or alloying schemes, which utilize the addition of other metal oxides into thin HfO 2 films, such as ZrO 2 , Al 2 O 3 , SiO 2 , rare earth oxides, and alkaline earth oxides, with the goal of stabilization of the metastable higher-k phases, have been thoroughly investigated. [16][17][18][19][20][21][22][23] Another approach that may offer a viable method to engineer the phase of pure HfO 2 is by depositing a metal gate on top of a thin HfO 2 film and then subjecting the film stack to a postmetal deposition anneal (PMA). Of the candidate metal gate materials, Ti-based metal gates, and in particular TiN, have been thoroughly evaluated and have found utilization in advanced MOSFET structures.…”