Change in the chemical state and thermal stability of HfO2 by the incorporation of Al2O3

Abstract

Al 2 O 3 incorporated HfO2 films grown by atomic layer deposition were investigated using various measurement tools. The accumulation capacitance of the Al2O3 incorporated into HfO2 film increases as the postannealing temperature increases because of changes in interfacial and upper layer thickness and in interfacial stoichiometry. The core-level energy state of a 15 Å thick film shows a shift to higher binding energy, as the result of silicate formation and Al2O3 incorporation. The incorporation of Al2O3 into the HfO2 film has no effect on silicate formation at the interface between the film and Si, while the ionic bonding characteristics and hybridization effects are enhanced compared to a pure HfO2 film. Any dissociated Al2O3 on the film surface is completely removed by a vacuum annealing treatment over 850 °C, while HfO2 contributes to Hf silicide formation on the surface of the film.

Transparent Conductive Oxide (TCO) Films for Organic Light Emissive Devices (OLEDs)

“…The O K edge NEXAFS spectra of the 300 o C-30 cycles sample were directly related to the oxygen p-projected density of states of ITO overlapped with that of HfO 2 , which consists of the four unoccupied hybridized orbitals, Hf 5d+O 2p , Hf 5d+O 2pσ, Hf 6s+O 2p, and Hf 6p+O 2p of the HfO 2 film. (Cho et al, 2004) The formation of a physically thick insulating HfO x layer between the anode and HTL, as confirmed by the NEXAFS measurement, significantly deteriorated the OLED performance, as previously shown in Figs. 6 and 7.…”

Microstructure and dielectric properties of La 2 O 3 doped amorphous SiO 2 films as gate dielectric material

“…As the size of the silicon-based MOSFET is reaching to the physical limitation with the rapid development of semiconductor industry, the traditional SiO 2 gate dielectrics cannot meet the requirement of high speed and low power due to large direct tunneling leakage [1]. The high current from the direct electronic tunneling deteriorates the reliability of the oxide film severely.…”

Electrical properties of MIS capacitor using low temperature electron beam gun—evaporated HfAlO dielectrics

“…The binding energies for O1s, C 1s, Hf4f and Al2p, are respectively 532, 18, 286 and 75 eV, close to the values obtained for similar films deposited by the ALD method [3]. The Si2p core-level XPS spectrum is shown in Fig.…”

“…However, HfO 2 has poor thermal stability, which results in an increase of leakage currents following thermal processes due to crystallization. The crystallization temperature of HfO 2 (400-450°C) can be increased by incorporation of Al 2 O 3 forming an HfAlO alloy, as was recently demonstrated [3][4][5] using two processing techniques: atomic layer deposition (ALD) and metal organic chemical vapor deposition.…”