Characterisation of Nd2O3 thick gate dielectric for silicon

Abstract

Thin neodymium films were prepared by the reactive synthesis method on Si (P) substrates to form MOS devices. The oxide films were characterised by UV absorption spectroscopy, X-ray fluorescence (EDXRF) and X-ray diffraction (XRD). The ac conductance and capacitance of the devices were studied as a function of frequency in the range 100 Hz-100 kHz, of temperature in the range 293-473 K and of gate voltage. It was proved that a suitable formalism to explain the frequency dependence of the ac conductivity and capacitance of the insulator is controlled by a universal power law based on the relaxation processes of the hopping or tunnelling of the current carriers between equilibrium sites. The temperature dependence of the ac conductance at the accumulation state shows a small activation energy of about 0.07 eV for a MOS device with amorphous neodymium oxide. The temperature dependence of the accumulation capacitance for a MOS structure with crystalline neodymium oxide shows a maximum at about 390 K; such a maximum was not observed for the structure with amorphous neodymium oxide. The method of capacitance-gate voltage (C-V g ) measurements was used to investigate the effect of annealing in air and in vacuum on the surface density of states (N ss ) at the insulator/semiconductor (I/S) interface. It was concluded that the density of surface states in the mid-gap increases by about five times while the density of the trapped charges in the oxide layer decreases by about eight times when the oxide crystallises into a polycrystalline structure.

Giant permittivity and good thermal stability of LiCuNb3O9-Bi(Mg0.5Zr0.5)O3solid solutions

“…Andersonlocalize charge carriers contribute to the conductivity by hopping processes, which makes the ac increase with the increase of frequency and attain a fixed value at low frequency. 23,24 Thermally activated defect carries, such as localized charge carries or oxygen vacancies, could result in ac positive correlation with the temperature. The measurement of frequency-dependent conductivity is used to analyze charge transfer, which could determine the presence of Anderson localization and provide information related to the characteristics of the charge carriers and process of transmissions such as tunneling through an energy barrier or hopping over.…”

“…The measurement of frequency-dependent conductivity is used to analyze charge transfer, which could determine the presence of Anderson localization and provide information related to the characteristics of the charge carriers and process of transmissions such as tunneling through an energy barrier or hopping over. The conductivity can be described by the "universal dielectric response" [23][24][25] ðf…”

Atomic spectrometry update. X-Ray fluorescence spectrometry

“…Publications on the characterisation of elements implanted in silicon were dominated this year by several papers from Dakhel. Using EDXRF and XRD 480 this group investigated Eu 2 O 3 as a thick gate dielectric for Si, 481 reported the electrical conduction and dielectric properties of Gd 2 O 3 grown on quartz and Si(p) substrates, 482 concentrated on Nd 2 O 3 films prepared by the reactive synthesis method to form MOS devices, 483,484 were concerned with (Gd-In) oxide films and [485][486][487] completed the output from the University of Bahrain with work on (Eu-In) oxide films. Putkomen et al 486 used XRF to analyse stoichiometry and look for possible impurities in Mg-Al-O films grown by atomic layer deposition (ALD) at 100-400 1C on to soda-lime-silicate glass and Si(100) substrates.…”

Paramagnetic rare-earth oxideNd2O3investigated by muon spin spectroscopy

“…In fact, as rareearth sesquioxides can present more than one crystal structure, for particular temperature and pressure conditions, they may exhibit several phases (spin, charge, orbital states), which can enhance the diversity in potential applications. Among rare-earth sesquioxides, Nd 2 O 3 assumes a prominent role in photonic applications, as a candidate high-κ dielectric, in sensor or catalyst applications [7][8][9][10][11][12][13].…”