Effective electrical passivation of Ge(100) for high-k gate dielectric layers using germanium oxide

Delabie, Annelies; Bellenger, Florence; Houssa, Michel; Conard, Thierry; Elshocht, Sven Van; Caymax, Matty; Heyns, Marc; Meuris, Marc

doi:10.1063/1.2773759

Cited by 284 publications

(210 citation statements)

References 15 publications

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“…An agglomeration reaction mechanism was reported for the growth of HfO 2 by HfCl 4 /H 2 O on such an HF-cleaned Ge surface. 17 The (NH 4 ) 2 S treated Ge surface consists of both Ge-OH and Ge-SH groups and the growth enhancement during ZrCl 4 /H 2 O deposition could be pointing to a possible agglomeration reaction mechanism where Cl ligands of the ZrCl 4 exchange with the remaining -OH groups on the Ge/S surface comparable to the agglomeration XPS reveals further information about the layer closure of Al 2 O 3 . The XPS spectra were measured after several days of air exposure.…”

Section: Resultsmentioning

confidence: 99%

Atomic Layer Deposition of High-κ Dielectrics on Sulphur-Passivated Germanium

Sioncke

Lin

Brammertz

et al. 2011

J. Electrochem. Soc.

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High mobility channels are currently being explored to replace the silicon channel in future CMOS technology nodes. However, until now the promising bulk properties are very difficult to translate into high transconductance due to a poor passivation of the interface between the gate dielectric and the channel. We have studied the S-passivation of the germanium surface combined with various high-permittivity dielectric gate stacks. (NH4)2S is used to achieve a S-terminated Ge surface. We found that the Ge/S/Al2O3 interface is superior to both the Ge/S/ZrO2 and Ge/S/HfO2 interfaces. Bi-layer stacks consisting of Ge/S/Al2O3/HfO2 or Ge/S/Al2O3/ZrO2 were built to achieve a gate stack with low EOT (Equivalent Oxide Thickness). In these bi-layer stacks, the Al2O3 thickness is reduced to a minimum without degradation of the interface properties. Rather thick Al2O3 interlayers (∼ 2 nm) are needed due to island growth on S-terminated Ge surface. A pMOSFET was built using a bi-layer gate stack (Ge/S/Al2O3/HfO2). The peak mobility of this device is > 200 cm2/Vs at an EOT of 1.5 nm.

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Section: Resultsmentioning

confidence: 99%

Atomic Layer Deposition of High-κ Dielectrics on Sulphur-Passivated Germanium

Sioncke

Lin

Brammertz

et al. 2011

J. Electrochem. Soc.

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“…7 Another approach is to cap the GeO 2 surface by the deposition of high-k dielectric layers. 8,9 Metal-oxide-doped GeO 2 such as yttrium-GeO 2 has attracted interest because of its stronger resistance to liquid water than pure GeO 2 . 10,11 The above studies indicate that GeO 2 is a key material in Ge-based MOSFETs, and it is still necessary to grasp the relationship between the physical/chemical properties of GeO 2 and its dielectric properties.…”

Section: Introductionmentioning

confidence: 99%

Comparative study of GeO2/Ge and SiO2/Si structures on anomalous charging of oxide films upon water adsorption revealed by ambient-pressure X-ray photoelectron spectroscopy

Mori

Oka

Hosoi

et al. 2016

Journal of Applied Physics

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The energy difference between the oxide and bulk peaks in X-ray photoelectron spectroscopy (XPS) spectra was investigated for both GeO 2 /Ge and SiO 2 /Si structures with thickness-controlled water films. This was achieved by obtaining XPS spectra at various values of relative humidity (RH) of up to $15%. The increase in the energy shift is more significant for thermal GeO 2 on Ge than for thermal SiO 2 on Si above $10 À4 % RH, which is due to the larger amount of water molecules that infiltrate into the GeO 2 film to form hydroxyls. Analyzing the origins of this energy shift, we propose that the positive charging of a partially hydroxylated GeO 2 film, which is unrelated to X-ray irradiation, causes the larger energy shift for GeO 2 /Ge than for SiO 2 /Si. A possible microscopic mechanism of this intrinsic positive charging is the emission of electrons from adsorbed water species in the suboxide layer of the GeO 2 film to the Ge bulk, leaving immobile cations or positively charged states in the oxide. This may be related to the reported negative shift of flat band voltages in metaloxide-semiconductor diodes with an air-exposed GeO 2 layer. Published by AIP Publishing.

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“…9,10 A broad range of solutions was considered, e.g. Ge controlled oxidation 6,11 and deposition of passivating interfacial layer ͑IL͒. 12 Recently, a study on ZrO 2 / GeO 2 stacks prepared by atomic oxygen-assisted MBD ͑Ref.…”

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confidence: 99%

Thermally induced permittivity enhancement in La-doped ZrO2 grown by atomic layer deposition on Ge(100)

Lamagna¹,

Wiemer²,

Baldovino³

et al. 2009

Applied Physics Letters

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La-doped ZrO2 thin films grown by O3-based atomic layer deposition directly on Ge(100) exhibit a dielectric constant of 29. Upon annealing in N2 at 400 °C, a high κ value >40 is extracted for film thickness below 15 nm. Compositional depth profiling allows to correlate this observation with a remarkable Ge interdiffusion from the substrate which is consistent with the stabilization of the tetragonal ZrO2 phase. Ge interaction with the oxide stack and the formation of a germanate-like interfacial region, which acts as an electrical passivation for the Ge surface, are also investigated.

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Effective electrical passivation of Ge(100) for high-k gate dielectric layers using germanium oxide

Cited by 284 publications

References 15 publications

Atomic Layer Deposition of High-κ Dielectrics on Sulphur-Passivated Germanium

Atomic Layer Deposition of High-κ Dielectrics on Sulphur-Passivated Germanium

Comparative study of GeO2/Ge and SiO2/Si structures on anomalous charging of oxide films upon water adsorption revealed by ambient-pressure X-ray photoelectron spectroscopy

Thermally induced permittivity enhancement in La-doped ZrO2 grown by atomic layer deposition on Ge(100)

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