Scattering mechanisms in shallow undoped Si/SiGe quantum wells

Laroche, Dominique; Huang, S.-H.; Nielsen, Erik; Chuang, Yen; Li, J. Y.; C, Liu; Lu, T. M.

doi:10.1063/1.4933026

Cited by 33 publications

(20 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The observed p 2D − V g and µ − p 2D dependences are in line with previous studies on shallow undoped Si and Ge/SiGe heterostructures 19,41 . At small electric fields, carrier tunneling can occur from the shallow Ge quantum well to defect states in the band-gap of the dielectric/SiGe interface.…”

Section: Discussionsupporting

confidence: 92%

“…In conclusion, by measuring key transport metrics at low temperatures, we have shown that shallow and undoped Ge/SiGe heterostructures are a promising low‐disorder platform for Ge quantum devices. The reported half‐million mobility sets new benchmarks for Si and Ge shallow‐channel H‐FETs, while even higher mobilities may be obtained by further improving the semiconductor/dielectric interface. Possible avenues in these directions include the removal of the native silicon oxide layer prior to high‐κ dielectric deposition and/or postmetallization thermal anneals.…”

Section: Discussionmentioning

confidence: 99%

“…We speculate that this mechanism is causing the observed upturn in the µ − p 2D dependence above a density of p 2D = 3 × 10 11 cm −2 , as described in ref. ]. At higher electric fields, the Fermi level aligns with the valence band‐edge at the dielectric/SiGe interface.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Shallow and Undoped Germanium Quantum Wells: A Playground for Spin and Hybrid Quantum Technology

Sammak

Sabbagh

Hendrickx

et al. 2019

Adv Funct Materials

127

126

View full text Add to dashboard Cite

Buried-channel semiconductor heterostructures are an archetype material platform for the fabrication of gated semiconductor quantum devices. Sharp confinement potential is obtained by positioning the channel near the surface; however, nearby surface states degrade the electrical properties of the starting material. Here, a 2D hole gas of high mobility (5 × 10 5 cm 2 V −1 s −1 ) is demonstrated in a very shallow strained germanium (Ge) channel, which is located only 22 nm below the surface. The top-gate of a dopant-less field effect transistor controls the channel carrier density confined in an undoped Ge/SiGe heterostructure with reduced background contamination, sharp interfaces, and high uniformity. The high mobility leads to mean free paths ≈ 6 µm, setting new benchmarks for holes in shallow field effect transistors. The high mobility, along with a percolation density of 1.2 × 10 11 cm −2 , light effective mass (0.09m e ), and high effective g-factor (up to 9.2) highlight the potential of undoped Ge/SiGe as a low-disorder material platform for hybrid quantum technologies.

show abstract

Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Shallow and Undoped Germanium Quantum Wells: A Playground for Spin and Hybrid Quantum Technology

Sammak

Sabbagh

Hendrickx

et al. 2019

Adv Funct Materials

127

126

View full text Add to dashboard Cite

show abstract

“…22 Furthermore, the advanced level of quantum control in these qubits allows to run quantum algorithms on two qubit processors. 15,16 By investigating quantum transport in Hall-bar shaped heterostructures field effect transistors, [23][24][25] key material metrics such as maximum mobility and percolation density are extracted. Electron mobility is a straightforward figure of merit to asses the overall quality of the 2DEG in the high density regime, where screening of impurity scattering is relevant.…”

Section: Multiplexed Quantum Transport Of Industrialmentioning

confidence: 99%

Multiplexed quantum transport using commercial off-the-shelf CMOS at sub-kelvin temperatures

et al. 2020

View full text Add to dashboard Cite

Continuing advancements in quantum information processing have caused a paradigm shift from research mainly focused on testing the reality of quantum mechanics to engineering qubit devices with numbers required for practical quantum computation. One of the major challenges in scaling toward large-scale solid-state systems is the limited input/output (I/O) connectors present in cryostats operating at sub-kelvin temperatures required to execute quantum logic with high fidelity. This interconnect bottleneck is equally present in the device fabrication-measurement cycle, which requires high-throughput and cryogenic characterization to develop quantum processors. Here we multiplex quantum transport of two-dimensional electron gases at sub-kelvin temperatures. We use commercial off-the-shelf CMOS multiplexers to achieve an order of magnitude increase in the number of wires. Exploiting this technology, we accelerate the development of 300 mm epitaxial wafers manufactured in an industrial CMOS fab and report a remarkable electron mobility of (3.9 ± 0.6) × 105 cm2/Vs and percolation density of (6.9 ± 0.4) × 1010 cm−2, representing a key step toward large silicon qubit arrays. We envision that the demonstration will inspire the development of cryogenic electronics for quantum information, and because of the simplicity of assembly and versatility, we foresee widespread use of similar cryo-CMOS circuits for high-throughput quantum measurements and control of quantum engineered systems.

show abstract

“…The starting material used in this study is a standard undoped Si/SiGe quantum well heterostructure grown in a ultra-high-vacuum chemical-vapor-deposition system (see Methods). Transport properties of induced 2D electrons in an un-patterned device from this material have been reported elsewhere 48 . A hole array with a period d = 200 nm in both directions is defined over a 90 μ m × 180 μ m region by locally ion milling the top gate (see Methods).…”

Section: Resultsmentioning

confidence: 99%

High-mobility capacitively-induced two-dimensional electrons in a lateral superlattice potential

Laroche

Huang

et al. 2016

Sci Rep

Self Cite

View full text Add to dashboard Cite

In the presence of a lateral periodic potential modulation, two-dimensional electrons may exhibit interesting phenomena, such as a graphene-like energy-momentum dispersion, Bloch oscillations, or the Hofstadter butterfly band structure. To create a sufficiently strong potential modulation using conventional semiconductor heterostructures, aggressive device processing is often required, unfortunately resulting in strong disorder that masks the sought-after effects. Here, we report a novel fabrication process flow for imposing a strong lateral potential modulation onto a capacitively induced two-dimensional electron system, while preserving the host material quality. Using this process flow, the electron density in a patterned Si/SiGe heterostructure can be tuned over a wide range, from 4.4 × 1010 cm−2 to 1.8 × 1011 cm−2, with a peak mobility of 6.4 × 105 cm2/V·s. The wide density tunability and high electron mobility allow us to observe sequential emergence of commensurability oscillations as the density, the mobility, and in turn the mean free path, increase. Magnetic-field-periodic quantum oscillations associated with various closed orbits also emerge sequentially with increasing density. We show that, from the density dependence of the quantum oscillations, one can directly extract the steepness of the imposed superlattice potential. This result is then compared to a conventional lateral superlattice model potential.

show abstract

Scattering mechanisms in shallow undoped Si/SiGe quantum wells

Cited by 33 publications

References 40 publications

Shallow and Undoped Germanium Quantum Wells: A Playground for Spin and Hybrid Quantum Technology

Shallow and Undoped Germanium Quantum Wells: A Playground for Spin and Hybrid Quantum Technology

Multiplexed quantum transport using commercial off-the-shelf CMOS at sub-kelvin temperatures

High-mobility capacitively-induced two-dimensional electrons in a lateral superlattice potential

Contact Info

Product

Resources

About