Correlation between channel mobility improvements and negative V&lt;inf&gt;th&lt;/inf&gt; shifts in III&amp;#x2013;V MISFETs: Dipole fluctuation as new scattering mechanism

Urabe, Yuji; Miyata, Noriyuki; Ishii, Hiroyuki; Itatani, Taro; Maeda, Tatsuro; Yasuda, Tetsuji; Yamada, Hisashi; Fukuhara, Noboru; Hata, Masahiko; Yokoyama, Masafumi; Taoka, Noriyuki; Takenaka, Mitsuru; Takagi, Shinichi

doi:10.1109/iedm.2010.5703310

Cited by 23 publications

(27 citation statements)

References 7 publications

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“…We have also confirmed that the combination of InGaAs and ALD Al 2 O 3 can lead to superior MOS interface properties [64], often attributed to the cleaning effect of TMA on InGaAs surfaces [41][42][43]. Also, it has been reported that sulfur (S) passivation [65,66] and surface nitridation [67,68] can improve the Al 2 O 3 /InGaAs MOS interface properties. However, one of the drawback of Al 2 O 3 is the low dielectric constant (~ 9), which is not enough to provide low EOT gate stacks with low gate leakage current.…”

Section: Iii-v Gate Stack Technologiessupporting

confidence: 78%

(Invited) MOS Interface Control of High Mobility Channel Materials for Realizing Ultrathin EOT Gate Stacks

et al. 2013

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One of the most critical issues for Ge/III-V MOSFETs, which have been regarded as a promising CMOS structure under sub 10 nm regime, is gate insulator formation satisfying the requirements of MOS interface quality and thin equivalent oxide thickness (EOT). In this paper, we focus on viable gate stack technologies realizing these requirements. As for Ge gate stacks, we present a ultrathin EOT Al 2 O 3 /GeO x /Ge gate stack fabricated by a plasma post oxidation method and pMOSFETs using this gate stack. The GeO x /Ge MOS interface properties are systemically examined, and the relations of the interface state density (D it ) with the GeO x thickness and the chemical conditions are studied. (100) Ge pMOSFETs using this gate stack is demonstrated with EOT down to 0.98 nm and high hole peak mobility of 401 cm 2 /Vs. As for InGaAs gate stacks, we show the impact of Al 2 O 3 inter-layers on interface properties of HfO 2 /InGaAs MOS interfaces. It is found that the insertion of 0.2-nm-thick ultrathin Al 2 O 3 inter-layer can effectively improve the HfO 2 /InGaAs interface properties such as the frequency dispersion and the stretch-out of C-V characteristics and D it . The 1-nm-thick capacitance equivalent thickness (CET) in the HfO 2 /Al 2 O 3 /InGaAs MOS capacitors is realized with good interface properties and low gate leakage of 2.4×10 -2 A/cm 2 .

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Section: Iii-v Gate Stack Technologiessupporting

confidence: 78%

(Invited) MOS Interface Control of High Mobility Channel Materials for Realizing Ultrathin EOT Gate Stacks

et al. 2013

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“…Improvement of the MIS interface is a central issue in order for III-V channels to be successfully implemented in future CMOS circuits. It is widely recognized that native oxides on III-V surfaces deteriorate the MIS interface properties [1,2], and many interface control methods have been proposed to remove or modify these oxides, such as surface passivation by wet oxide etching [3,4], sulfur passivation [5,6], plasma cleaning [7,8], nitridation [9,10], Si deposition [11,12], and atomic layer deposition (ALD) using reducing reactants [13,14]. Among these studies, the effects of Al 2 O 3 ALD on III-V surfaces have been investigated extensively [15,16].…”

Section: Introductionmentioning

confidence: 99%

Initial Processes of Atomic Layer Deposition of Al2O3 on InGaAs: Interface Formation Mechanisms and Impact on Metal-Insulator-Semiconductor Device Performance

et al. 2012

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Interface-formation processes in atomic layer deposition (ALD) of Al2O3 on InGaAs surfaces were investigated using on-line Auger electron spectroscopy. Al2O3 ALD was carried out by repeating a cycle of Al(CH3)3 (trimethylaluminum, TMA) adsorption and oxidation by H2O. The first two ALD cycles increased the Al KLL signal, whereas they did not increase the O KLL signal. Al2O3 bulk-film growth started from the third cycle. These observations indicated that the Al2O3/InGaAs interface was formed by reduction of the surface oxides with TMA. In order to investigate the effect of surface-oxide reduction on metal-insulator-semiconductor (MIS) properties, capacitors and field-effect transistors (FETs) were fabricated by changing the TMA dosage during the interface formation stage. The frequency dispersion of the capacitance-voltage characteristics was reduced by employing a high TMA dosage. The high TMA dosage, however, induced fixed negative charges at the MIS interface and degraded channel mobility.

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“…It has already been reported that (111)A GaAs MOSFETs can also provide the higher mobility that (100) GaAs MOSFETs [70] and that the (111)A surfaces can significantly modulate the MOS interface structure and the electrical properties [71]. We have demonstrated that (111)A-surface InGaAs MOSFETs with TaN/Al 2 O 3 gate stacks can provide much higher mobility than the (100) one [68,72]. Here, the pre-gate treatment of the InGaAs surfaces was carried out by etching in a diluted HCl solution followed by immersion in an (NH 4 ) 2 S solution.…”

Section: N-gamentioning

confidence: 79%

“…It is found that the high enhancement factor of 2.2x against the Si mobility is obtained in high E eff region. While this mobility improvement might be attributable partly to the reduction in scattering due to surface dipole fluctuation [68], further experimental and theoretical studies are needed to identify the physical mechanism of the surface orientation dependence. However, these experimental findings strongly suggest that the surface orientation engineering is quite effective in III-V MOSFET as well.…”

Section: N-gamentioning

confidence: 99%

(Invited) MOS Interface Control Technologies for III-V/Ge Channel MOSFETs

et al. 2011

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MOSFETs using channel materials with low effective mass have been regarded as strongly important for obtaining high current drive and low supply voltage CMOS under sub 10 nm regime. From this viewpoint, attentions have recently been paid to III-V and Ge channels. However, one of the most critical issues for realizing Ge/III-V MOSFETs is gate insulator formation with superior MOS interface quality on Ge/III-V. In this paper, we focus on the possible solutions for gate stack technologies on Ge/III-V. As for Ge, GeO 2 /Ge interfaces have been regarded as promising. However, these interfaces have still employed thick GeO 2 layers. Recently, we have succeeded in thin EOT gate stacks with Ge oxide interfacial layers by using ECR plasma post oxidation. The high quality Al 2 O 3 /GeO x /Ge gate stacks were fabricated by exposing the ALD Al 2 O 3 /Ge structures to ECR oxygen plasma and oxidizing the Ge surface through the very thin ALD Al 2 O 3 layer. We present our recent results of the interface properties using this interface. As for InGaAs channels, we have also proposed a novel interfacial control technology utilizing InGaAs surface nitridation by ECR nitrogen plasma and successive post metallization annealing. This interfacial layer combined with an ECR sputtering SiO 2 or an ALD Al 2 O 3 gate insulator is shown to reduce D it down to low order of 10 11 cm -2 eV -1 . The physical origin of this D it reduction and the role of the nitridation are discussed.

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Correlation between channel mobility improvements and negative V<inf>th</inf> shifts in III–V MISFETs: Dipole fluctuation as new scattering mechanism

Cited by 23 publications

References 7 publications

(Invited) MOS Interface Control of High Mobility Channel Materials for Realizing Ultrathin EOT Gate Stacks

(Invited) MOS Interface Control of High Mobility Channel Materials for Realizing Ultrathin EOT Gate Stacks

Initial Processes of Atomic Layer Deposition of Al2O3 on InGaAs: Interface Formation Mechanisms and Impact on Metal-Insulator-Semiconductor Device Performance

(Invited) MOS Interface Control Technologies for III-V/Ge Channel MOSFETs

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