摘要:

This letter concerns a generalization of the method presented in recent papers for the determination of the galvanomagnetic coefficients, especially those of magnetoresistance, for the case of crystals with low symmetry. The central idea is the search of one of the principal directions of the zero‐field resistivity and the application of the Wasscher method for anisotropic materials in a circular flat sample containing the other two principal directions. The determination of the magnetoresistance coefficients is obtained by the peculiar influence of the magnetic field on the resistivity anisotropy leading to the magnetoresistance skewness effect.

ISSN:0003-6951    

DOI:10.1063/1.95226

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

SiC films were grown on (100) silicon substrates using a Si molecular beam and a C+ion beam with the same impingement rates of Si atoms and C+ions. Reflection high‐energy electron diffraction analysis showed that 3C‐SiC grows epitaxially on the Si substrate at temperatures ranging from 820 to 1000 °C and at the ion energies of 50 and 100 eV with the ion current density of about 3 &mgr;A/cm2. Auger electron spectroscopy measurements showed that the films obtained were stoichiometric and do not contain impurities such as oxygen. The influence of surface treatments of Si substrates was also studied.

ISSN:0003-6951    

DOI:10.1063/1.95227

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The strain and lattice disorder introduced by room temperature implantation (N, Si, Zn) into strained‐layer superlattices (SLS) of In0.2Ga0.8As/ GaAs have been measured by cantilever‐beam techniques and by channeled and random Rutherford backscattering spectrometry. These measurements indicate that a maximum lateral compressive stress of ∼5×109dyn/cm2is induced for all the ions at fluences corresponding to deposited energy densities of about 1020keV/cm3into collisional processes. The compositional modulation of the SLS is maintained at fluences which exceed the yield stress value even in the presence of additional implantation‐induced stress and significant numbers of atomic displacements.

ISSN:0003-6951    

DOI:10.1063/1.95228

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The first direct images of dopant distributions in Si have been observed using scanning transmission electron microscopy, by detecting Rutherford‐scattered transmitted electrons. Strong atomic number (Z) contrast is obtained allowing images to be formed of Bi at concentrations of the order of 0.2 to 1 at. % and of Sb at concentrations of 0.5 to 6 at. %. The image contrast from cross‐section specimens correlated closely with the dopant concentration profiles determined by x‐ray microanalysis and with Rutherford ion backscattering analysis of the bulk materials. This technique should prove extremely valuable for studying dopant segregation phenomena in semiconductors.

ISSN:0003-6951    

DOI:10.1063/1.95229

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Thin ⟨110⟩ silicon crystals were bombarded with 14 MeV oxygen ions in a transmission channeling geometry. The ions exited the crystals through a thin layer of Au or Ag, and scattered ions were detected at a glancing exit angle. Spectra were collected for each consecutive dose and analyzed to determine the number of disordered silicon atoms produced per dose. Disorder at the metal–silicon interface was observed that increased linearly with dose from 5×1015to 5×1016oxygen ions/cm2. Beam heating, and nuclear and electronic stopping power are discussed as possible sources of the disorder.

ISSN:0003-6951    

DOI:10.1063/1.95230

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The annealing of the lattice damage induced by Be‐ion implantation in GaAs has been studied by spectroscopic ellipsometry and Raman scattering after each step of an isochronal thermal treatment. These two optical (i.e., nondestructive) techniques are shown to be very sensitive both to the lattice recovery and to the electrical activation of the implants. It has been observed that the latter process occursafterthe lattice perfection recovery atT=550 °C, while for the ultimate annealing temperatures (T>750 °C) a significant Be redistribution takes place resulting in a decrease of the electrical activity which is confirmed by differential Hall effect measurements.

ISSN:0003-6951    

DOI:10.1063/1.95231

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The role of oxygen contamination in determining the properties, particularly the resistance, of the cosputtered tantalum disilicide has been investigated. As‐deposited films with silicon/tantalum atomic ratios in the range of 1.9 to 2.5 were monitored. There is no noticeable effect of the small amounts of oxygen (≲0.5 at. %) on the stress and the reactive ion etching characteristics of these films. The resistance, however, changed significantly due to the presence of oxygen even in a concentration as small as 0.02 at. %. The results are discussed in view of the changing Si/Ta ratio and oxygen concentration and the possible hopping electron conduction mechanism.

ISSN:0003-6951    

DOI:10.1063/1.95232

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Optical absorption measurements have been performed on unmodified and on ion‐implanted lead lanthanum zirconate titanate ceramics using the photothermal deflection spectroscopy technique. Bulk absorption coefficients depend on the average grain size of the material while the absorption associated with the ion‐damaged layers does not. The damage‐induced surface absorptance correlates well with the photosensitivity observed in implanted PLZT devices, supporting earlier models for the enhanced imaging efficiency of the materials.

ISSN:0003-6951    

DOI:10.1063/1.95233

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Iron‐constantan thin film thermocouples overlaid with Ge layers 1 &mgr;m thick are used to measure the temperature‐time dependence during irradiation with nanosecond Nd glass laser pulses. The response of the thermocouple is fast enough to allow the measurements of the temperature rise and fall. The obtained temperature values are in good agreement with the thermal model of laser annealing.

ISSN:0003-6951    

DOI:10.1063/1.95234

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

We have measured the first infrared luminescence spectra of In0.53Ga0.47As with 10‐ps time resolution. From the spectra we have obtained the carrier distribution functions at various delays for two different initial plasma densities. Our results provide a direct measurement of the carrier energy loss rate to the lattice, which we find to be about an order of magnitude slower than predicted from a simple model. We also find that the energy loss rate is surprisingly insensitive to carrier density at high densities.

ISSN:0003-6951    

DOI:10.1063/1.95235

出版商:AIP    

年代:1984

数据来源: AIP