Properties of Thermal Gadolinium Oxide Films on Silicon

Ko, Hong-Hsi; Chang, Liann‐Be; Jeng, Ming–Jer; Kuei, Ping-Yu; Horng, K. Y.

doi:10.1143/jjap.44.3205

Cited by 10 publications

(10 citation statements)

References 14 publications

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“…The binding energies of the developed Pr 2 O 3 and Gd 2 O 3 films were 934 and 1189 eV in the 3d core level and 116 V and 143 eV in the 4d core level. 6 These measurements match the standard results in the handbook of XPS. Figure 3 also plots the high signal intensities of Pr 2 O 3 and Gd 2 O 3 ; high-quality high-k insulators can be obtained by the electron-beam evaporation of Pr and Gd at a high oxygen flow rate.…”

supporting

confidence: 75%

Comprehensive Study of GaAs MOSFETs Using Gadolinium Oxide and Praseodymium Oxide Layers

Chiu

Lin

et al. 2008

J. Electrochem. Soc.

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The high-dielectric-constant ͑high-k͒ gadolinium oxide layer ͑Gd 2 O 3 ͒ and praseodymium oxide layer ͑Pr 2 O 3 ͒ are demonstrated as gate dielectric insulator materials in GaAs metal-oxide-semiconductor field-effect transistors ͑MOSFETs͒ using in situ high oxygen flow rate electron-beam deposition technology. The dielectric constants of the Gd 2 O 3 and Pr 2 O 3 layers developed in this study were 9.2 and 9.8, respectively. The Schottky gate turn-on voltages of GaAs MOSFETs with Gd 2 O 3 and Pr 2 O 3 insulators were 2.23 and 2.25 V, respectively, representing an improvement on the conventional p-type high electron mobility transistors ͑0.85 V͒. Moreover, the Gd 2 O 3 MOSFETs had a higher thermal stability and thermal linearity than the Pr 2 O 3 MOSFET ͑tem-perature range 100-400 K͒ due to its high binding energy, as revealed by X-ray photoelectron spectroscopy. GaAs metal-oxide-semiconductor field-effect transistors ͑MOS-FETs͒ potentially have advantages over Si-based MOSFETs for use in high-power monolithic microwave integrated circuits because of their high electron mobility and high breakdown voltage. According to previous investigations, the Schottky gate leakage current and I ds -V ds hysteresis, which are both sensitive to the interface between GaAs and the gate electrode metal, limit the device linearity.1,2 Additionally the thermally stable high-k MOSFET architecture for GaAs field-effect transistor is superior to the metal-semiconductor Schottky interface in maintaining simultaneously a high channel control ability and a low insulator leakage current. Based on the works reported by other groups, 3,4 rare-earth metal oxide high-k layers were demonstrated on GaAs MOSFET using molecular beam epitaxy ͑MBE͒ and liquid phase epitaxy. The dielectric constants of the rare-earth metal oxide high-k layers were 15-30, and these reported devices exhibited stable and reliable performance. The gate metal was deposited using an electron-beam evaporator after the high-k material growth environment for these processes, and the fixed charge in the metal-oxide interface was an additional problem. The complicated gate formation approach is also difficult to be used in high-volume industrial production. In this investigation, Pr and Gd were electron-beam evaporated with a high oxygen flow rate to produce a high-quality high-k oxide layer after the gate recess process, and then Ti/Au metal was deposited in situ in the same highvacuum chamber. This novel technology can improve the Pr and Gd oxidization ratio, which was a major drawback in our previous study. 5 The dielectric constants of Gd 2 O 3 and Pr 2 O 3 developed using this technology were 9.2 and 9.8, respectively. Accordingly, Pr 2 O 3 MOSFETs achieved a higher drain-to-source current ͑I ds ͒ and a more stable pinch-off voltage ͑V p ͒ than Gd 2 O 3 MOSFETs due to their higher dielectric constant and channel modulation ability. Furthermore, to apply these high-k GaAs MOSFETs in microwave power amplifiers, which usually generate much heat during operation, temperature-...

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supporting

confidence: 75%

Comprehensive Study of GaAs MOSFETs Using Gadolinium Oxide and Praseodymium Oxide Layers

Chiu

Lin

et al. 2008

J. Electrochem. Soc.

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“…Thus, previously grown SiO 2 in the stacked structure has diffusion resistance. 3,9) However, the thermal oxidation of metal films/SiO 2 /Si stacked structures has been examined in detail in only a few studies. For further investigation of the interaction between atoms, and understanding both the binding characteristics and depth distributions of such structures, we grew thick dielectric films.…”

mentioning

confidence: 99%

Growth Evolution of ZrO₂ from Deposited Zr Metal during Thermal Oxidation

Hsieh

Kuei

et al. 2006

Jpn. J. Appl. Phys.

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Pulsating white dwarf stars can be used as astrophysical laboratories to constrain the properties of weakly interacting particles. Comparing the cooling rates of these stars with the expected values from theoretical models allows us to search for additional sources of cooling due to the emission of axions, neutralinos, or neutrinos with magnetic dipole moment. In this work, we derive an upper bound to the neutrino magnetic dipole moment (µ ν ) using an estimate of the rate of period change of the pulsating DB white dwarf star PG 1351+489. We employ state-of-the-art evolutionary and pulsational codes which allow us to perform a detailed asteroseismological period fit based on fully DB white dwarf evolutionary sequences. Plasmon neutrino emission is the dominant cooling mechanism for this class of hot pulsating white dwarfs, and so it is the main contributor to the rate of change of period with time (Π) for the DBV class. Thus, the inclusion of an anomalous neutrino emission through a nonvanishing magnetic dipole moment in these sequences notably influences the evolutionary timescales, and also the expected pulsational properties of the DBV stars. By comparing the theoreticalΠ value with the rate of change of period with time of PG 1351+489, we assess the possible existence of additional cooling by neutrinos with magnetic dipole moment. Our models suggest the existence of some additional cooling in this pulsating DB white dwarf, consistent with a non-zero magnetic dipole moment with an upper limit of µ ν 10 −11 µ B . This bound is somewhat less restrictive than, but still compatible with, other limits inferred from the white dwarf luminosity function or from the color-magnitude diagram of the Globular cluster M5. Further improvements of the measurement of the rate of period change of the dominant pulsation mode of PG 1351+489 will be necessary to confirm our bound.

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“…In the previous studies [7,17], the SiO 2 film with smooth and tight surface grown slowly by anodic oxidation had good blocking function to prevent the growth of Gd-silicate between the Gd 2 O 3 layer and the Si substrate. Therefore, we expected this SiO 2 barrier film also had good blocking function to prevent the growth of Zr-silicate.…”

Section: Resultsmentioning

confidence: 93%

“…Therefore, the development of alternative high-k materials with large band gap, large conduction band offset, minimum interfacial SiO 2 , low leakage current, low surface roughness, and high thermal stability in direct contact with Si are required in the future ULSI devices. Of all the high-k materials Y 2 O 3 [3], Al 2 O 3 [4], Ta 2 O 5 [5], Gd 2 O 3 [6,7], HfO 2 [8], STO [9], and ZrO 2 [10,11] have been widely studied. Efforts are being focused on altering the gate stack, rather than just the gate dielectric.…”

Section: Introductionmentioning

confidence: 99%