Masao Tokumura

Fabrication of Si:H Alloy with Plenty of –SiH3 by Reactive Sputtering onto Low Temperature Substrate

Si:H alloy with strong infrared absorption bands due to the –SiH3 group was fabricated by means of a planar magnetron r.f. sputtering technique in hydrogen gas onto a low temperature substrate. The content of the –SiH3 group increases greatly by cooling down the single crystal silicon wafer substrate to about -60°C. The deposition rate was 1200 A/min. The deposit Si:H alloy is composed of microcrystalline grains with a uniform polyhedron or spherical shape and a uniform diameter of 100 A.

Magnetic Field Dependence of Ballistic Heat-Pulse Scattering in As-Doped Ge

Heat-pulse propagation along the [100] axis of As (1.5 ×10 14 /cm 3 and 0.9 ×10 15 /cm 3 )-doped Ge has been studied as a function of the magnetic field H //[100] and of the heat-pulse temperatures ranging from 6.6 K to 9.3 K. It is shown that the transmitting heat-pulse intensity detected by CdS bolometer increases with increasing magnetic field up to 60 kG at sample temperatures ranging from 1.8 K to 4.2 K. The magnetic field dependence of the detected heat-pulse amplitude is compared with a calculation based on the Suzuki-Mikoshiba theory.

Low temperature process for preparing a diamond-like-carbon film from graphite by H2-gas chemical sputtering

Abstract By means of hydrogen gas chemical sputtering of a graphite target, we have succeeded in the preparation of high insulating diamond-like-carbon (an a-C: H) film by RF- and DC-power. A noteworthy point is that the film can be prepared quite easily by a low temperature (room temperature ∼ 150°C) process. The film contains about 0.8 H/C of hydrogen atoms, and it is estimated that 80 or 90% of the bonding between neighbouring carbon atoms (except the C-H bond) is by a sp3 hybridization bond. The energy gap is from 1.2 to 3.0 eV, which increases with the content of hydrogen atoms as a general tendency. The resistivity is about 1012 Ω cm, and the density of the dangling bond is estimated to be of the order of 10 17 cm 3 . Diamond grains of about a few hundred A in diameter appeared in the film annealed at 1000°C in vacuum.

Ballistic Heat-Pulse Transport in Sb-Doped Ge under Magnetic Field

The magnetic field and the heater temperature dependence of the attenuation of ballistic heat-pulse with transverse polarization propagating along the [100] axis were measured in Sb (0.38 or 2.1 ×10 15 /cm 3 ) doped Ge at liquid He temperatures under the magnetic field up to 60 kG in the [100] direction. The experimental results show opposite trend to theoretical calculation of the phonon scattering based on the shrinkage effect of the donor wave function. On the other hand, a theoretical prediction which takes account of the scattering of the heat-pulse phonons by either polar or homo-polar pairs under the magnetic field in the [100] direction shows qualitative agreement with the experimental results.

Anomalous Behavior of Acoustic Attenuation in Ge: Sb under [001] Magnetic Field

Magnetic field effect on the acoustic attenuation at 0.83 and 3.35 GHz in 0.45 and 1.7×10 16 Sb/cm 3 doped Ge was measured in tlte [001] magnetic field up to 60 kG at liquid He temperatures. The experimental results are summarized as follows: (1) The attenuation decreases with the field and shows a minimtun at 27 kG and then increases. (2) The position of the minimum point is nearly independent of the donor concentration, the temperature, and the frequency. (3) The magnitude of the effect shows a sub-linear dependence on the donor concentration. The experimental results were compared with a theoretical calculation based on the shrinkage effect of the donor wave function to the phonon scattering by the neutral donor electrons at the ground state. The theory explains the decrease of the attenuation at lower fields, but does not explain the anomalous increase at higher fields.

Magnetic Field Dependence of Ballistic Heat-Pulse Attenuation in Sb Doped Ge

The magnetic field and the frequency dependence of the attenuation of the ballistic heat-pulse propagating in Sb (0.4–0.9x1015/cm3) doped Ge were measured at liquid He temperatures up to 60 kG. We used the CdS thin film bolometer which is useful in the magnetic field. The heat-pulse was propagated along the [111] or [100] axis, and the magnetic field \( \overset{\lower0.5em\hbox{

Heat-Pulse Scattering in P-Doped Ge under Magnetic Field

\smash{\scriptscriptstyle\rightharpoonup}

Magnetic Field Dependence of Acoustic Attenuation in Uniaxially Compressed Sb Doped Ge

}} {H} \) was applied along the direction of the wave vector \( \overset{\lower0.5em\hbox{

ESCA compositional profiles and electrical properties of diamond-like carbon film/Si MIS structure

\smash{\scriptscriptstyle\rightharpoonup}

ACOUSTIC ATTENUATION BY SHALLOW DONORS IN GERMANIUM IN A MAGNETIC FIELD

}} {q} \). In the former case \(\left( {\left[ {111} \right]////} \right)\), the Zeeman splitting of the ground states of the neutral donor electrons reflects directly on the attenuation. In the latter case \(\left( {\left[ {100} \right]////} \right)\), the magnetic field dependence of the attenuation mainly arises from the shrinkage effect of the donor wave function.