Quantum transport in sputtered, epitaxial Si/Si1−xGex heterostructures

Abstract

Radio–frequency magnetron sputter epitaxy was employed for the synthesis of n–type modulation doped Si/Si1−xGex heterostructures. Si channels were grown coherently on sputtered, compositionally graded Si1−xGex buffers of low defect density, and remotely doped with phosphorus by plasma assisted gas phase doping. Magnetotransport measurements on these films revealed Shubnikov–de Haas oscillations in the longitudinal and the integer quantum Hall effect in the transverse magnetoresistance, demonstrating the presence of a two–dimensional electron gas. At T=1.6 K and sheet densities of 1012 cm−2, electron mobilities as high as 15 800 cm2/V s give evidence of the excellent structural and electronic properties achievable by the sputter growth technique.

Scalable Synthesis of Uniform Few-Layer Hexagonal Boron Nitride Dielectric Films

“…Physical vapor deposition could avoid the complex set of interrelated growth parameters governing CVD processes. While commonly associated with polycrystalline thin films, for example, in metallurgical coatings or transparent conducting oxides, magnetron sputtering has been used to grow epitaxial metals, , compounds, and semiconductor heterostructures, including high electron mobility modulation-doped quantum wells . Here we demonstrate the growth of high quality few-layer BN films with controlled thickness using reactive magnetron sputtering of B in N 2 /Ar, a scalable, industry-compatible process that uses only benign, nontoxic reagents.…”

“…Physical vapor deposition could avoid the complex set of interrelated growth parameters governing CVD processes. While commonly associated with polycrystalline thin films, for example, in metallurgical coatings or transparent conducting oxides, magnetron sputtering has been used to grow epitaxial metals,22,23 compounds,24 and semiconductor heterostructures,25 including high electron mobility modulation-doped quantum wells 26. Here we demonstrate the growth of high quality few-layer BN films with controlled thickness using reactive magnetron sputtering of B in N 2 /Ar, a scalable, industry-compatible process that uses only benign, nontoxic reagents.The glow discharge of the magnetron sputtering process plays two important roles in the growth of BN films (Figure1a):27,28 (i) evaporation of B by collision cascades due to the impact of energetic Ar + ions on a solid B target; and (ii) generation of nitrogen radicals via dissociation of gas phase N 2 by free electrons and ions in the plasma.…”

10.1007/s11451-008-2019-7

“…Most often in experiment, these corrections exhibit a quadratic dependence of the sample conductivity on the magnetic field strength [18][19][20]. This fact is usually attributed either to the electronelectron interaction or to the electron scattering on the long-range fluctuation potential of charged impurities in the barrier layers and on the external surface.…”

“…The term ∆σ cor (H) responsible for the NMR of the sample and originating from the electron-electron interaction has a square-root dependence on magnetic field, according to theory [18][19][20][21]: (1) It is convenient to choose = 1 T for a characteristic magnetic field magnitude, though it is not really critical, since we use the parameter β = σ 0 / in calculations. The best fit of the experimental to theoretical dependences is found with the values of the coefficient β given in Table 2 by iterations using the method of conjugate gradients and Eq.…”