High-k gate stack on GaAs and InGaAs using in situ passivation with amorphous silicon

Oktyabrsky, S.; Tokranov, V.; Yakimov, Michail M.; Moore, Richard; Koveshnikov, S.; Tsai, W.; Zhu, Feng; Lee, Jack C.

doi:10.1016/j.mseb.2006.08.018

Cited by 78 publications

(42 citation statements)

References 11 publications

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“…Recently, we have demonstrated that an in-situ deposited amorphous Si interface passivation layer (IPL) of at least 1.5 nm thickness can be used to reduce interface state density and prevent the Fermi level pinning at GaAs or InGaAs interface with ex-situ high-k oxide [7,8]. It was further shown [9] that the IPL layer thickness can be significantly reduced or it can even be eliminated if the high-k oxide is deposited in-situ without exposure of the III-V surface to environment.…”

Section: Introductionmentioning

confidence: 99%

Interface properties of MBE-grown MOS structures with InGaAs/InAlAs buried channel and in-situ high-k oxide

Oktyabrsky

Tokranov

Koveshnikov

et al. 2009

Journal of Crystal Growth

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Section: Introductionmentioning

confidence: 99%

Interface properties of MBE-grown MOS structures with InGaAs/InAlAs buried channel and in-situ high-k oxide

Oktyabrsky

Tokranov

Koveshnikov

et al. 2009

Journal of Crystal Growth

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“…In order to sustain a better gate capacitance scalability for metal-oxide-semiconductor (MOS) device application, high-k dielectrics have been deposited onto the III-V semiconductor substrates, such as GaAs and InGaAs [2][3][4][5][6][7][8][9][10][11][12].…”

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confidence: 99%

Synchrotron radiation photoemission spectroscopic study of band offsets and interface self-cleaning by atomic layer deposited HfO2 on In0.53Ga0.47As and In0.52Al0.48As

Kobayashi

Chen

Sun

et al. 2008

Applied Physics Letters

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whereas in-situ vacuum annealing removes surface arsenic pile-up. After the atomic layer deposition of HfO 2 , native oxides were considerably reduced compared to that in as-received epi-layers, strongly suggesting the self-clean mechanism. Valence and conduction band offsets are measured to be 3.37±0.1eV, 1.80±0.3eV for In 0.53 Ga 0.47 As and 3.00±0.1eV, 1.47±0.3eV for In 0.52 Al 0.47 As, respectively.

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“…We note that under the in situ deposition techniques employed here, no As-O-Si bonding is detected in contrast to previous reports. 4 The amount of SiO x that arises as the Si is deposited on the differently prepared surfaces as calculated using Si 2p XPS spectra also differs ͑not shown͒. On an NH 4 OH treated surface exposed to a Si deposition of ϳ1.1 nm, 40% of the Si 2p signal is from some form of SiO x rather than Si-Si bonds.…”

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confidence: 99%

Frequency dispersion reduction and bond conversion on n-type GaAs by in situ surface oxide removal and passivation

Hinkle

Sonnet

Vogel

et al. 2007

Applied Physics Letters

101

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The method of surface preparation on n-type GaAs, even with the presence of an amorphous-Si interfacial passivation layer, is shown to be a critical step in the removal of accumulation capacitance frequency dispersion. In situ deposition and analysis techniques were used to study different surface preparations, including NH 4 OH, Si-flux, and atomic hydrogen exposures, as well as Si passivation depositions prior to in situ atomic layer deposition of Al 2 O 3 . As-O bonding was removed and a bond conversion process with Si deposition is observed. The accumulation capacitance frequency dispersion was removed only when a Si interlayer and a specific surface clean were combined. © 2007 American Institute of Physics. ͓DOI: 10.1063/1.2801512͔GaAs has once again attracted attention as an alternative substrate for metal oxide semiconductor ͑MOS͒ technologies. The advantages of GaAs over silicon are well-known, mainly having a higher electron mobility and breakdown voltage as well as a direct band gap suggesting GaAs for a wide range of devices. The elimination of anomalous frequency dispersion of the accumulation capacitance of GaAs MOS devices is a major motivation behind surface and interface treatment studies. Previous reports have attributed this dispersion, viz., the reduction of maximum capacitance with increasing measurement frequency, to a high density of interface states which results in Fermi-level pinning. Recent studies have indicated that the disruption of As-O bonding at the dielectric/GaAs interface results in an unpinned interface. 1 Revisiting earlier works on Si passivation of GaAs surfaces ͑see, for example, Refs. 2 and 3͒, recent reports of Si deposition on GaAs for surface passivation in conjunction with high-k dielectrics ͑for example, Refs. 4 and 5͒, have stimulated this study using in situ deposition and analysis methods. In this letter, in situ analysis techniques are used to correlate differences in electrical characteristics caused by different surface treatments employed on the technologically relevant n-type GaAs surface for use in enhancement mode transistors.The samples used in this work were n-type Si-doped GaAs wafers with a doping concentration of 5 ϫ 10 17 cm −3 . One set of samples was degreased in acetone, methanol, and isopropyl alcohol for 1 min each, followed by a 3 min etch in 29% NH 4 OH, 6 and dried with N 2 , while another set was prepared, in situ with no chemical treatment, using a hydrogen cracker source ͑cell temperature of 1400°C, P H 2 =1 ϫ 10 −6 mbar͒ producing atomic H with a substrate temperature of 430°C for 30 min. 7,8 Silicon of various thicknesses was deposited at room temperature on treated GaAs by e-beam evaporation ͑deposition rate= 18-132 Å / min in a multitechnique deposition/characterization system ͑base pressure= 2 ϫ 10 −11 mbar͒. 9 MOS capacitors were made using such treated surfaces followed by atomic layer deposition ͑ALD͒ of 10 nm of Al 2 O 3 using trimethylaluminum ͑TMA͒ and H 2 O at 300°C in an adjacent chamber and ex situ, rf sputtered TaN as the gat...

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High-k gate stack on GaAs and InGaAs using in situ passivation with amorphous silicon

Cited by 78 publications

References 11 publications

Interface properties of MBE-grown MOS structures with InGaAs/InAlAs buried channel and in-situ high-k oxide

Interface properties of MBE-grown MOS structures with InGaAs/InAlAs buried channel and in-situ high-k oxide

Synchrotron radiation photoemission spectroscopic study of band offsets and interface self-cleaning by atomic layer deposited HfO2 on In0.53Ga0.47As and In0.52Al0.48As

Frequency dispersion reduction and bond conversion on n-type GaAs by in situ surface oxide removal and passivation

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