Complementary Metal–Oxide–Silicon Field-Effect-Transistors Featuring Atomically Flat Gate Insulator Film/Silicon Interface

Kuroda, Rihito; Teramoto, Akinobu; Nakao, Yukihisa; Suwa, Tomoyuki; Konda, M.; Hasebe, Rui; Li, Xiang; Isogai, Tatsunori; Tanaka, Hiroaki; Sugawa, Shigetoshi; Ohmi, Tadahiro

doi:10.1143/jjap.48.04c048

Cited by 41 publications

(52 citation statements)

References 18 publications

(28 reference statements)

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“…With Si, several methods have been developed such as sacrificial oxidation, 5) wet chemical treatment, 6) argon or hydrogen (H 2 ) gas annealing. [7][8][9][10] Although it is well known that surface treatment in high vacuum is effective for obtaining an atomically flat surface on the Ge substrate, 11) no investigation of atomically flat Ge surfaces by using conventional process technology has been reported. Therefore, in this paper, we investigated the impact of sacrificial oxidation and H 2 annealing on the surface morphology of Ge.…”

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confidence: 99%

Step and Terrace Formation on Ge(111) Surface in H$_{2}$ Annealing

Nishimura¹,

Lee²,

Nagashio³

et al. 2012

Appl. Phys. Express

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This paper reports the atomically flat surface formation of germanium (Ge) (111) in hydrogen gas (H2) annealing. The (111)-oriented Ge substrate was annealed at 350–850 °C, and the surface morphology was measured using an atomic force microscope. A step and terrace formation was observed on the Ge(111) surface in H2 annealing at the temperature ranging from 500 to 850 °C. Furthermore, the surface morphology after 2.4-nm-thick GeO2 formation at 400 °C on Ge(111) is also discussed from the viewpoint of the Ge surface oxidation mechanism.

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confidence: 99%

Step and Terrace Formation on Ge(111) Surface in H$_{2}$ Annealing

Nishimura¹,

Lee²,

Nagashio³

et al. 2012

Appl. Phys. Express

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“…[12][13][14] The Si surface thus had monoatomic steps with a height of 0.136 nm and atomically flat terraces with a width of approximately 150 nm. The surface roughness in each terrace was 0.03 nm; it was less than the detection limit of atomic force microscopy.…”

Section: Methodsmentioning

confidence: 99%

Structural Analyses of Thin SiO₂Films Formed by Thermal Oxidation of Atomically Flat Si Surface by Using Synchrotron Radiation X-Ray Characterization

Nagata

Ogura

Hirosawa

et al. 2015

ECS J. Solid State Sci. Technol.

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Partially crystalline structures in thin SiO 2 films formed by thermal oxidation of atomically flat Si surface were investigated by performing X-ray reflectometry and grazing incidence X-ray diffraction measurements. The densities of the SiO 2 films were higher than those of amorphous SiO 2 films, especially at the SiO 2 /Si interface. The structure of thermally grown SiO 2 has been expected to be amorphous, but sharp diffraction peaks were observed in GIXRD measurements. The diffraction peaks tended to reflect a cristobalite-like structure with preferential orientations to the Si substrate. In addition, the lattice spacing of the cristobalite-like structure was estimated from the GIXRD measurement and found to be isotropically distorted. Silicon dioxide (SiO 2 ) thin films of less than 10 nm are among the important dielectric materials for semiconductor devices, and many research studies on this material are actively being performed. [1][2][3][4][5][6] It is necessary to understand the formation process of the oxidation film to get high quality insulation characteristic. Thin SiO 2 films provide excellent electrical insulation and interface state densities, and they can readily be obtained using thermal oxidation. Generally, thermally grown SiO 2 film has an amorphous structure based on six-membered rings consisting of Si-O triangular pyramids. However, it was also reported that relatively thick SiO 2 film has a residual ordered structure reflecting the crystalline structure of the Si substrate.7-11 However, the detailed structure of the SiO 2 film has not been sufficiently revealed by these studies yet. In particular, the evaluation of thin SiO 2 films of less than 10 nm is very difficult because of the small scattering volume and the probably low degree of order in the structure. In this study, X-ray reflectometry (XRR) and grazing incident-angle X-ray diffraction (GIXRD) using synchrotron radiation were performed to evaluate the structures of thin SiO 2 films on the atomically flat surface. ExperimentalThin SiO 2 films were fabricated on the Si (001) substrate after the atomic-order planarization process consisting of thermal annealing at 1200• C for 30 min in a pure Ar atmosphere. 12-14 The Si surface thus had monoatomic steps with a height of 0.136 nm and atomically flat terraces with a width of approximately 150 nm. The surface roughness in each terrace was 0.03 nm; it was less than the detection limit of atomic force microscopy. Then, thermal oxidation was carried out in a pure oxygen atmosphere with three different temperatures. We prepared a SiO 2 sample grown with an 800• C process for 82 min, with a 900• C process for 13 min and with an 1100• C process for 30 sec. These thicknesses of SiO 2 films were approximately 7 nm. The purities of used oxygen gas were 99.9995%. GIXRD measurements were performed at SPring-8 BL46XU (2012A1597) using synchrotron radiation with a photon energy of 10 keV. The penetration depth of the X-rays into the sample varied rapidly near the critical angle. 15,16 The grazing an...

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“…And a small trap density insulator film should be formed above the PD for suppressing the fixed charge generation due to trapping of the carriers excited by high photon energy UV-light. Here, the atomically flat Si surface is formed by annealing a bare Si surface wafer at around 800°C or above in an ultra-pure Ar ambient with a residue H 2 O concentration of 30 ppb or less [20,21,22]. By this process, a flat Si surface formed by atomic terrace and mono-atomic layer steps are obtained [20].…”

Section: Introductionmentioning

confidence: 99%

“…By this process, a flat Si surface formed by atomic terrace and mono-atomic layer steps are obtained [20]. In addition, by an alkali-free wet cleaning process in dark ambient condition for bare Si wafer to suppress the local Si etching and by an oxygen radical oxidation process with isotropic oxidation reaction, the atomic flatness level is maintained through the device fabrication process [20,21]. through 7 nm thick oxide film.…”

Section: Introductionmentioning

confidence: 99%

Si image sensors with wide spectral response and high robustness to ultraviolet light exposure

Kuroda

Sugawa

2014

IEICE Electron. Express

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Si image sensors with a wide spectral response range and a high robustness to ultraviolet light exposure based on flattened Si surface are described in this paper. A photodiode (PD) fabrication technology is developed to form a thin surface high concentration layer with steep dopant profile on flattened Si surface. Due to this, PDs with a wide spectral response ranging from 200 to 1000 nm is achieved with almost 100% internal quantum efficiency to ultraviolet light (UV-light) waveband. In addition, high robustness of light sensitivity and dark current toward UV-light exposure is obtained. The developed technology is applied to in-pixel buried PDs of photodiode arrays and a CMOS image sensor. The advanced performances of fabricated sensors are verified with experimental results.

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Complementary Metal–Oxide–Silicon Field-Effect-Transistors Featuring Atomically Flat Gate Insulator Film/Silicon Interface

Cited by 41 publications

References 18 publications

Step and Terrace Formation on Ge(111) Surface in H$_{2}$ Annealing

Step and Terrace Formation on Ge(111) Surface in H$_{2}$ Annealing

Structural Analyses of Thin SiO₂Films Formed by Thermal Oxidation of Atomically Flat Si Surface by Using Synchrotron Radiation X-Ray Characterization

Si image sensors with wide spectral response and high robustness to ultraviolet light exposure

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Complementary Metal–Oxide–Silicon Field-Effect-Transistors Featuring Atomically Flat Gate Insulator Film/Silicon Interface

Cited by 41 publications

References 18 publications

Step and Terrace Formation on Ge(111) Surface in H$_{2}$ Annealing

Step and Terrace Formation on Ge(111) Surface in H$_{2}$ Annealing

Structural Analyses of Thin SiO2Films Formed by Thermal Oxidation of Atomically Flat Si Surface by Using Synchrotron Radiation X-Ray Characterization

Si image sensors with wide spectral response and high robustness to ultraviolet light exposure

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Structural Analyses of Thin SiO₂Films Formed by Thermal Oxidation of Atomically Flat Si Surface by Using Synchrotron Radiation X-Ray Characterization