Electrical characterization of germanium p-channel MOSFETs

Shang, Huiling; Okorn-Schimdt, H.; Ott, J. A.; Kozlowski, P.; Steen, S.E.; Jones, E.C.; Wong, H.-S. Philip; Hanesch, W.

doi:10.1109/led.2003.810879

Cited by 181 publications

(89 citation statements)

References 6 publications

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“…Significant research on the high-j gate dielectrics HfO 2 , 17 23 and germanium-oxynitride 24 has been studied on the (100)Ge metal-oxide semiconductor (MOS) devices. Although excellent device performances were achieved using high-j gate dielectrics on bulk (100)Ge and oxide/(100)Ge band alignment properties, little attention has been devoted on the integration of high-j gate dielectrics on the epitaxial (110)Ge, (111)Ge, and the associated energy band alignment at each interface.…”

Section: Introductionmentioning

confidence: 99%

Energy band alignment of atomic layer deposited HfO2 oxide film on epitaxial (100)Ge, (110)Ge, and (111)Ge layers

Hudait

Zhu

2013

Journal of Applied Physics

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Articles you may be interested inLow-temperature plasma-enhanced atomic layer deposition of HfO2/Al2O3 nanolaminate structure on Si J. Vac. Sci. Technol. B 33, 01A101 (2015) Crystallographically oriented epitaxial Ge layers were grown on (100), (110), and (111)A GaAs substrates by in situ growth process using two separate molecular beam epitaxy chambers. The band alignment properties of atomic layer hafnium oxide (HfO 2 ) film deposited on crystallographically oriented epitaxial Ge were investigated using x-ray photoelectron spectroscopy (XPS). Valence band offset, DE v values of HfO 2 relative to (100)Ge, (110)Ge, and (111)Ge orientations were 2.8 eV, 2.28 eV, and 2.5 eV, respectively. Using XPS data, variation in valence band offset, DE V ð100ÞGe > DE V ð111ÞGe > DE V ð110ÞGe, was obtained related to Ge orientation. Also, the conduction band offset, DE c relation, DE c ð110ÞGe > DE c ð111ÞGe > DE c ð100ÞGe related to Ge orientations was obtained using the measured bandgap of HfO 2 on each orientation and with the Ge bandgap of 0.67 eV. These band offset parameters for carrier confinement would offer an important guidance to design Ge-based p-and n-channel metal-oxide field-effect transistor for low-power application.

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Section: Introductionmentioning

confidence: 99%

Energy band alignment of atomic layer deposited HfO2 oxide film on epitaxial (100)Ge, (110)Ge, and (111)Ge layers

Hudait

Zhu

2013

Journal of Applied Physics

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“…Recently, high electron mobility in Ge n-channel metal-insulation-semiconductor field-effect transistors (n-MISFETs) with a sub-nm equivalent oxide thickness gate stack has been demonstrated, owing to appropriate gate stack designing, [1][2][3][4] in addition to the high hole mobility in Ge p-MISFET, which has already been reported. 5,6) Therefore, the most serious challenges for realizing practical scaled Ge CMOS are currently the reduction in parasitic resistance and the suppression of off-state leakage at the source=drain of MISFETs. In particular, to reduce the contact resistance at the metal=Ge interface, a reduction in Schottky barrier height (SBH) at the interface is definitely required.…”

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confidence: 99%

Reexamination of Fermi level pinning for controlling Schottky barrier height at metal/Ge interface

Nishimura

Yajima

Toriumi

2016

Appl. Phys. Express

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The element metal/germanium (Ge) interface exhibits a strong Fermi level pinning (FLP), which is usually characterized on the basis of Ge side semiconductor properties. In this work, we demonstrate that metal properties significantly affect the Schottky barrier height (SBH) on Ge. Metallic germanides show both FLP alleviation and a clear substrate orientation dependence of SBH on Ge, despite the nearly perfect FLP and very slight orientation dependence in the element metal case. As a result, ohmic characteristics are observed at germanide/n-Ge (111) junctions. The metal properties required to alleviate the FLP on Ge are also discussed. © 2016 The Japan Society of Applied Physics G ermanium (Ge) is one of the promising semiconductor materials for high-performance complementary metal-oxide-semiconductors (CMOSs) in the next generation owing to its high electron and hole mobilities. Recently, high electron mobility in Ge n-channel metal-insulation-semiconductor field-effect transistors (n-MISFETs) with a sub-nm equivalent oxide thickness gate stack has been demonstrated, owing to appropriate gate stack designing, [1][2][3][4] in addition to the high hole mobility in Ge p-MISFET, which has already been reported. 5,6) Therefore, the most serious challenges for realizing practical scaled Ge CMOS are currently the reduction in parasitic resistance and the suppression of off-state leakage at the source=drain of MISFETs. In particular, to reduce the contact resistance at the metal=Ge interface, a reduction in Schottky barrier height (SBH) at the interface is definitely required. However, the Fermi level is almost perfectly pinned to the valence band edge of Ge at the metal=Ge interface for various element metals. 7,8) This fact suggests that the Fermi level pinning (FLP) on Ge may be limited by an intrinsic mechanism. Therefore, understanding the FLP mechanism and controlling the SBH on n-Ge are strongly required.Recently, FLP alleviation has been demonstrated in ultrathin-film [GeO 2 , 9) Al 2 O 3 , 9) GeN, 10) SiN,11) MgO,12) Si,13) ZnO, 14) TiO 2 , 15) W-encapsulating Si, 16) indium tin oxide (ITO) 17) ] insertion at the element metal=Ge interface. When the direct metal=Ge interface is replaced by the metal= ultrathin film and ultrathin film=Ge interfaces, the strong FLP at the direct metal=Ge interface becomes less significant. Nevertheless, since the interface layer resistance is added, the direct metal=Ge interface with a low SBH is more preferable from the viewpoint of contact resistance reduction. With respect to the direct metal=Ge interface, it has recently been reported that the SBHs at epitaxial Fe 3 Si, 18) α-TiGeN, 19) epitaxial Mn 5 Ge 3 , 20) epitaxial NiGe 2 , 21) graphene, 22) and Sn 23) =n-Ge interfaces are relatively low, which deviates from the trend of strong FLP. 7,8) Some of them 18,20,21,23) considered that the FLP on Ge might not be determined by an intrinsic but extrinsic origin. It is inferred that those two kinds of experimental results may include a key aspect to understand the FLP mechani...

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“…22 The calculated mobility of the planar FET, 313 cm 2 /V s, was larger than we found for our system, although this is not surprising given that the surfaces of the Ge nanowire FETs were unpassivated. Higher mobilities and smaller subthreshold slopes should be obtainable for future Ge nanowire FETs by deposition of a Ge oxynitride 23 or SiGe capping layer that could limit charge traps at the nanowire surface. Our bottom-up approach to device fabrication will allow such passivation to be carried out in situ following Ge nanowire synthesis, and this should lead to improved characteristics for both n-and p-type Ge nanowire FETs.…”

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confidence: 99%

Growth and transport properties of complementary germanium nanowire field-effect transistors

Greytak

Lauhon

Gudiksen

et al. 2004

Applied Physics Letters

369

254

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n- and p-type Ge nanowires were synthesized by a multistep process in which axial elongation, via vapor–liquid–solid (VLS) growth, and doping were accomplished in separate chemical vapor deposition steps. Intrinsic, single-crystal, Ge nanowires prepared by Au nanocluster-mediated VLS growth were surface-doped in situ using diborane or phosphine, and then radial growth of an epitaxial Ge shell was used to cap the dopant layer. Field-effect transistors prepared from these Ge nanowires exhibited on currents and transconductances up to 850 μA/μm and 4.9 μA/V, respectively, with device yields of >85%.

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Electrical characterization of germanium p-channel MOSFETs

Cited by 181 publications

References 6 publications

Energy band alignment of atomic layer deposited HfO2 oxide film on epitaxial (100)Ge, (110)Ge, and (111)Ge layers

Energy band alignment of atomic layer deposited HfO2 oxide film on epitaxial (100)Ge, (110)Ge, and (111)Ge layers

Reexamination of Fermi level pinning for controlling Schottky barrier height at metal/Ge interface

Growth and transport properties of complementary germanium nanowire field-effect transistors

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