Electron Mobility Enhancement in GeSn n-Channel MOSFETs by Tensile Strain

Chuang, Yen; Liu, Chia-You; Luo, Guang-Li; Li, Jiun-Yun

doi:10.1109/led.2020.3041051

Cited by 15 publications

(11 citation statements)

References 16 publications

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“…For higher electron mobility, a 0.46% tensile strain was introduced to Ge 0.96 Sn 0.04 ; due to the introducing of tensile strain, the carrier population in the Γ valley was higher. Thus, the electron mobility of GeSn nMOSFETs was further improved to 698 cm 2 /V·s [ 215 ].…”

Section: Gesn Transistorsmentioning

confidence: 99%

Review of Si-Based GeSn CVD Growth and Optoelectronic Applications

et al. 2021

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GeSn alloys have already attracted extensive attention due to their excellent properties and wide-ranging electronic and optoelectronic applications. Both theoretical and experimental results have shown that direct bandgap GeSn alloys are preferable for Si-based, high-efficiency light source applications. For the abovementioned purposes, molecular beam epitaxy (MBE), physical vapour deposition (PVD), and chemical vapor deposition (CVD) technologies have been extensively explored to grow high-quality GeSn alloys. However, CVD is the dominant growth method in the industry, and it is therefore more easily transferred. This review is focused on the recent progress in GeSn CVD growth (including ion implantation, in situ doping technology, and ohmic contacts), GeSn detectors, GeSn lasers, and GeSn transistors. These review results will provide huge advancements for the research and development of high-performance electronic and optoelectronic devices.

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Section: Gesn Transistorsmentioning

confidence: 99%

Review of Si-Based GeSn CVD Growth and Optoelectronic Applications

et al. 2021

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“…Lattice strain in semiconductors enables modification of their electronic band structure, including their band gap, electronic charge density, and phonon frequency [1][2][3][4][5][6]. In particular, strained III-V and group-IV semiconductors have been widely investigated theoretically and experimentally because lattice strain can be applied in these materials through heterointerfaces formed via epitaxial growth techniques, leading to advances in the field of condensed-matter physics and to various applications [7][8][9][10][11][12][13][14]. Recent studies of two-dimensional semiconductors have revealed an alternative strain effect on the electronic band structures and band gaps even in graphene [15,16], transition-metal dichalcogenides [17,18], and monolayer honeycomb elements [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Effect of Strain on Room-Temperature Spin Transport in Si0.1Ge0.9

Naitô

Yamada²,

Wagatsuma³

et al. 2022

Phys. Rev. Applied

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We report a strain effect on spin transport in semiconductors that exhibit Ge-like conduction bands at room temperature. Using four-terminal nonlocal spin-transport measurements in lateral spin-valve devices, we experimentally estimate the spin diffusion length (λ) of Ge and strained Si 0.1 Ge 0.9 with two different carrier concentrations. Despite the Ge-like electronic band structure, the obtained λ of a strained Si 0.1 Ge 0.9 is comparable to that of a Si channel. We discuss a possible mechanism of the strain-induced enhancement of λ at room temperature. As a consequence, we demonstrate the electrical detection of 5-μm lateral spin transport in the strained Si 0.1 Ge 0.9 by applying an electric field at room temperature.

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“…To continue Moore’s law for future technology nodes, high-mobility channels are required for high-performance applications. Among group-IV materials, GeSn is a promising candidate due to its high carrier mobilities , and its compatibility with the Si CMOS technology. A high hole mobility of 845 cm 2 /V·s was demonstrated in a GeSn p-MOSFET due to a reduced effective mass by compressive strain .…”

Section: Introductionmentioning

confidence: 99%

“…A high hole mobility of 845 cm 2 /V·s was demonstrated in a GeSn p-MOSFET due to a reduced effective mass by compressive strain . Tensile-strained GeSn n-MOSFETs with a high electron mobility of ∼700 cm 2 /V·s were recently reported by Chuang et al, which is attributed to the increased electron population in Γ valley of the conduction band . For high-performance applications, low series resistances such as source/drain (S/D) and contact resistances are needed.…”

Section: Introductionmentioning

confidence: 99%

“…1 Tensile-strained GeSn n-MOSFETs with a high electron mobility of ∼700 cm 2 /V•s were recently reported by Chuang et al, which is attributed to the increased electron population in Γ valley of the conduction band. 2 For highperformance applications, low series resistances such as source/ drain (S/D) and contact resistances are needed. While a low contact resistivity of <10 −9 Ω•cm 2 has been demonstrated in a metal/p-GeSn contact, 3 for metal/n-Ge(Sn) contacts, their high electron Schottky barrier height (SBH) due to Fermi-level pinning (FLP) leads to a large contact resistivity of 10 −6 −10 −7 Ω•cm 2 .…”

Section: Introductionmentioning

confidence: 99%

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Schottky Barrier Height Modulation of Metal/n-GeSn Contacts Featuring Low Contact Resistivity by in Situ Chemical Vapor Deposition Doping and NiGeSn Alloy Formation

Chuang

Liu

Kao

et al. 2021

ACS Appl. Electron. Mater.

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GeSn complementary metal-oxide-semiconductor (CMOS) devices have attracted much attention for future VLSI technology nodes due to high carrier mobility. However, Fermilevel pinning in metal/n-GeSn contacts leads to high contact resistivity and limits GeSn CMOS devices for high-performance logic applications. In this work, we investigate Schottky characteristics and contact resistivity in the metal/n-GeSn contacts. Highquality n-GeSn layers were epitaxially grown by chemical vapor deposition with an in situ doping technique with a high carrier activation rate of 73% up to a doping concentration of ∼1.3 × 10 20 cm −3 . The electron Schottky barrier heights of the metal/n-GeSn contacts with different Sn fractions and metal work functions were extracted by an I−T method. The results show that the Fermi level is pinned at an energy level slightly above the valence band maximum. The Schottky barrier height is highly correlated with the GeSn band gap energy and decreases with the Sn fraction. The contact resistivity of the metal/n-Ge 0.9 Sn 0.1 contacts was extracted by a refined transmission line model and effectively reduced by increasing the doping concentration in the n-GeSn films. A post-metal annealing step at 400 °C was performed to further reduce the Schottky barrier height by forming NiGeSn alloys. A record low contact resistivity of ∼1.5 × 10 −7 Ω•cm 2 is achieved without any surface treatment. This is attributed to the reduced Schottky barrier height by increasing the Sn fraction in the n-GeSn film and the reduced Schottky barrier width due to the high carrier density achieved by in situ doping.

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Electron Mobility Enhancement in GeSn n-Channel MOSFETs by Tensile Strain

Cited by 15 publications

References 16 publications

Review of Si-Based GeSn CVD Growth and Optoelectronic Applications

Review of Si-Based GeSn CVD Growth and Optoelectronic Applications

Effect of Strain on Room-Temperature Spin Transport in Si0.1Ge0.9

Schottky Barrier Height Modulation of Metal/n-GeSn Contacts Featuring Low Contact Resistivity by in Situ Chemical Vapor Deposition Doping and NiGeSn Alloy Formation

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