| 1. |
- Cho, C. R., et al.
(author)
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Na0.5K0.5NbO3 thin films for MFIS_FET type non-volatile memory applications
- 2002
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In: Integrated Ferroelectrics. - 1058-4587 .- 1607-8489. ; 49, s. 21-30
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Journal article (peer-reviewed)abstract
- Na0.5K0.5NbO3(NKN) thin films have been prepared on Pt80Ir20, SiO2/Si, and Ta2O5/Si substrates for ferroelectric non-volatile memory applications. Ferroelectric hysteresis loops for Au/NKN/Pt80Ir20 vertical capacitor yielded remnant polarization of 12 muC/cm(2) and coercive field similar to20 kV/cm. Significant flat-band voltage V-FB shifts with buffer layer thickness in Au/NKN/SiO2/Si structures have been attributed to the intermixing between Na and K alkali ions and SiO2 layer. On the other hand, Au/NKN/Ta2O5/Si structure exhibited wide memory window without significant V-FB deviations, low leakage currents, and rather long retention time at zero bias.
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| 2. |
- Johansson, M, et al.
(author)
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HfO2 gate dielectrics on strained-Si and strained-SiGe layers
- 2003
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In: Semiconductor Science and Technology. - : IOP Publishing. - 0268-1242 .- 1361-6641. ; 18:9, s. 820-826
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Journal article (peer-reviewed)abstract
- We report on materials and device characterization of polycrystalline HfO2 gate dielectrics grown by atomic layer deposition (ALD) at 600 degreesC on strained-Si and strained-SiGe layers. No change in the diffusion profile of Hf into the Si substrate was observed for temperatures in the range 900-1100 degreesC for 20 min. The strain status in the Si layer remained unaltered after HfO2 deposition and an interface state density of similar to1 x 10(11) cm(-2) eV(-1) was obtained for the thicker HfO2 films. The breakdown fields were in the range 2-5 MV cm(-1), which is high compared to HfO2 films grown at higher temperatures. The leakage current was reduced by more than five orders of magnitude for the thin HFO2 with an EOT of 1.25 nm and ultra-thin cap (2.5-3 nm) layers on Si0.77Ge0.23/Si, though high interface state densities (similar to1 x 10(12) cm(-2) eV(-1)) were observed. The carrier transport through these HfO2 films was found to follow Frenkel-Poole emission over a wide range of applied gate voltages.
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| 3. |
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| 4. |
- Schuisky, M., et al.
(author)
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Ferroelectric Bi4Ti3O12 thin films on Pt-coated silicon by halide chemical vapor deposition
- 2000
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 88:5, s. 2819-2824
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Journal article (peer-reviewed)abstract
- A halide chemical vapor deposition technique has been developed to grow highly c-axis oriented submicron Bi4Ti3O12 films onto Pt(200 nm)/Ti(20 nm)/SiO2(1200 nm)/Si(100) substrates. BiI3, TiI4, and oxygen were used as precursors. The total gas pressure was found to be the critical processing parameter to grow films with good crystalline and dielectric properties. The 300 nm thick Bi4Ti3O12 films fabricated at 700 degrees C and total gas pressure of 3.8 Torr exhibit the best dielectric performance: dielectric constant around 200 and loss tan delta similar to 0.018 at 100 kHz, remnant polarization of 5.3 mu C/cm(2), induced polarization of 14.9 mu C/cm(2) at 560 kV/cm, coercive field of 150 kV/cm, electrical tunability of 51% at 350 kV/cm, resistivity of 2x10(9) Omega cm, and leakage current as low as 3x10(-5) A/cm(2) at 100 kV/cm. The effect of weak reduction of the remnant polarization and coercive field has been observed in the temperature range from 300 to 77 K and ascribed to the in-plane orientation of the polar a axis in fabricated Bi4Ti3O12 films.
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| 5. |
- Sundqvist, J., et al.
(author)
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Atomic layer deposition of Ta2O5 using the TaI 5 and O2 precursor combination
- 2003
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In: Chemical Vapor Deposition. - : Wiley. - 0948-1907 .- 1521-3862. ; 9:5, s. 245-248
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Journal article (peer-reviewed)abstract
- Thin films of tantalum oxide have been deposited on Si(100) substrates using atomic layer deposition (ALD) employing the TaI5 and O 2 precursor combination. Growth was studied in the temperature region 400 to 700°C. The resulting films were found to be iodine-free above 450°C, and consisted of the polycrystalline orthorhombic ß-Ta 2O5 phase. The growth rate was found to be strongly dependent on the deposition temperature, reaching a maximum of 0.17 nm cycle-1 at 600°C.
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| 6. |
- Yousif, M. Y. A., 1963, et al.
(author)
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HfO2 for strained-Si and strained-SiGe MOSFETs
- 2003
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In: ESSDERC 2003. Proceedings of the 33rd European Solid-State Device Research - ESSDERC '03. - 1930-8876. - 0780379993 ; , s. 255-
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Conference paper (peer-reviewed)abstract
- We report on HfO2 gate dielectrics grown by atomic layer deposition (ALD) at 600°C on strained-Si and strained-SiGe layers. The strain status in the Si layer remained unaltered after HfO2 deposition and an interface state density of ~1×1011 cm-2 eV-1 was obtained for the case of thick HfO2 films. The breakdown fields were in the range 2-5 MV/cm, which is high compared to HfO2 films grown at higher temperatures. The leakage current was reduced by more than five orders of magnitude for the case of a thin HfO2 film with an EOT of 1.25 nm and ultra-thin cap (2.5-3 nm) layers on Si0.77Ge0.23/Si. The carrier transport through these HfO2 films was found to follow Frenkel-Poole emission over a wide range of applied gate voltage
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