Investigation of two-dimensional hole gases in Si/SiGe heterostructures

Guldner, Y.; Berroir, Jean-Marc; Vieren, J. P.; Voos, M.; Sagnes, I.; Badoz, P. A.; Warren, P.; Dutartre, D.

doi:10.1103/physrevb.48.12312

Cited by 15 publications

(27 citation statements)

References 15 publications

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“…Usually another doped layer is grown near the cap surface of inverted structure to prevent this effect, 8 but it may cause a second 2-DHG at the normal interface. 9 Here we report on how the proximity of the surface charges and boron segregation affect the 2-DHG at the inverted interface of Si 0.8 Ge 0.2 MD structures that have been grown by solid-source molecular-beam epitaxy ͑MBE͒.…”

mentioning

confidence: 99%

Issues on the molecular-beam epitaxial growth of p-SiGe inverted-modulation-doped structures

Sadeghzadeh

Parry

Phillips

et al. 1999

Applied Physics Letters

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The influence of boron segregation and silicon cap-layer thickness on two-dimensional hole gases ͑2-DHGs͒ has been investigated in Si/Si 0.8 Ge 0.2 /Si inverted-modulation-doped heterostructures grown by solid-source molecular-beam epitaxy. Boron segregation, which is significant in structures with small spacer layers, can be suppressed by growth interruption after the boron doping. How growth interruption affected the electrical properties of the 2-DHG and the boron doping profile as measured by secondary ion mass spectroscopy are reported. We report also on the role played by the unpassivated silicon cap, and compare carrier transport at the normal and inverted interfaces.

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mentioning

confidence: 99%

Issues on the molecular-beam epitaxial growth of p-SiGe inverted-modulation-doped structures

Sadeghzadeh

Parry

Phillips

et al. 1999

Applied Physics Letters

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“…The distribution of the twc-dimensional holes present in symmetrically doped Si/Sil-%Gez heterostructures is very much dependent on the well width. For well widths of the order of about 50 nm Shubnikov-de Haas experiments reveal the presence of two parallel, highly equivalent channels much like a double heterostructure [3]. For lower well widths, below 10 or 20 nm, the channels come closer and the distribution starts resembling that of a conventional quantum well 141.…”

Section: Introductionmentioning

confidence: 93%

Mobility of a Two‐Dimensional Hole Gas in a SiSiGeSi Quantum Well Based on a New Wave Function

Kundu

Raychaudhuri

Ghosh

1996

Physica Status Solidi (b)

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The distribution of two-dimensional holes in a SiGe quantum well (QW) depends significantly on the well width, as it is nearly sinusoidal for very narrow wells and becomes of double heterojunction type for wider wells. In this paper a new wave function has been proposed to account for the distribution at all well widths. The temperature variation of mobility has been studied along with the well width dependence of the mobility. The relative contributions of different scattering mechanisms have been studied. The effect of screening has also been included. The results when compared with mobilities computed for other standard wave functions agree well with the sinusoidal wave function for very thin wells and with the Fang-Howard wave function for much wider wells. For intermediate well widths, the mobilities based on the new wave function show better agreement with experimental data than for the other two wave functions that are, respectively, valid only at the two extremes.

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“…5,6 Structures with a controllable hole density in the channel are useful in understanding the scattering mechanisms limiting mobility of holes confined near to normal ͑Si on SiGe͒ and inverted ͑SiGe on Si͒ interfaces of the Si/SiGe/Si quantum wells, so gating these structures allows one to change the hole sheet density systematically in a single device. MOS gating of undoped Si/SiGe/Si structures 4 and back-gating of normal MD structures 7,8 has been reported to study the transport properties of holes confined at the normal interface.…”

Section: ͓S0003-6951͑00͒03802-x͔mentioning

confidence: 99%

“…The low mobility ͑at 4.2 K͒ of holes confined at the Si/SiGe/Si structures has been a matter of controversy 4,6,10,11 and interface charge, roughness, strain fluctuation, and alloy scattering potentials have been addressed for it. For example, in Ref.…”

Section: ϫ2mentioning

confidence: 99%

Top-gating of p-Si/SiGe/Si inverted modulation-doped structures

Sadeghzadeh

2000

Applied Physics Letters

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Low-temperature electrical properties of two-dimensional hole gases (2-DHGs) in Si/Si0.8Ge0.2/Si inverted modulation-doped structures have been investigated at different hole densities using a metal semiconductor gate sputtered on top of these structures. The 2-DHG which is supplied to the inverted interface of Si/SiGe/Si quantum well by a Si boron-doped layer spatially grown beneath the alloy, was controlled in the range of 1.5–7.8×1011 cm−2 hole density by biasing the top gate. With increasing 2-DHG sheet density, the hole wave function of these structures expands and moves away from inverted interface, consequently the mobility enhances. These results may be understood theoretically by elaborating the role of interface charge, roughness, and alloy scattering mechanisms in limiting the mobility of holes at the inverted interface.

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Investigation of two-dimensional hole gases in Si/SiGe heterostructures

Cited by 15 publications

References 15 publications

Issues on the molecular-beam epitaxial growth of p-SiGe inverted-modulation-doped structures

Issues on the molecular-beam epitaxial growth of p-SiGe inverted-modulation-doped structures

Mobility of a Two‐Dimensional Hole Gas in a SiSiGeSi Quantum Well Based on a New Wave Function

Top-gating of p-Si/SiGe/Si inverted modulation-doped structures

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