摘要:

Calculations have been made of the barrier heights and recombination velocities at semiconductor grain boundaries subject to uniform illumination with above‐band‐gap light. A detailed balance approach has been coupled with a solution of the current continuity equation to yield a full solution of the problem subject to the approximation that majority carrier currents can be properly described by thermionic emission expressions. Silicon bicrystal data are presented and shown to be in good agreement with the predictions of the theory.

ISSN:0021-8979    

DOI:10.1063/1.329202

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A method has been developed for determining the stress profiles of neon‐implanted garnet layers. This determination is done nondestructively by computer simulation of rocking curves observed in x‐ray double‐crystal diffraction. The method has been tested for three different neon implantations at energies of 100, 300, and 500 keV with doses of 1×1014, 2×1014, and 1×1014ions/cm2, respectively. A comparison is made with an earlier destructive method based on stepwise etching of the layer. In addition the resulting profiles are compared to and show good agreement with profiles obtained from relative etching rates of the implanted films.

ISSN:0021-8979    

DOI:10.1063/1.329203

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

This paper reports some phenomena of the nucleation of oxygen precipitates in silicon, and proposes a nucleation model consistent with these observations. In addition to the principal tool of infrared absorption for the measurement of dissolved oxygen concentrations, the distribution of the dissolved and the precipitated oxygen was characterized by a method combining thermal conversion and spreading resistance profiling, a method combining thermal conversion and copper plating, and a selective etching. Heat treatments were carried out in argon ambients at temperatures from 800 to 1150°C, for time up to 96 h. In many cases samples from seed‐end segments of Czochralski crystals, with uniform initial oxygen distribution, exhibited alternating zones of fast and slow precipitation. Both the low density and the clustering aspects of the precipitates in the slow precipitation zones are reminiscent of precipitates formed in oxidizing ambients I previously reported. The density of precipitates was observed to increase with annealing time, and for sufficiently long time, with the decrease of annealing temperature. In sequential annealing processes, a low‐temperature preanneal was found to accelerate the precipitation in a subsequent higher‐temperature anneal. These two phenomena are evidence of a homogeneous nucleation process. It was also observed that a high‐temperature preanneal tended to irreversibly retard the precipitation in a subsequent lower‐temperature anneal. Both this phenomenon and the zonal variation of precipitation rates are not expected from the conventional concept of homogeneous nucleation, which involves only the agglomeration of solute atoms. However, both can be explained by a modified homogeneous nucleation model that involves both the oxygen atoms and certain active centers, most probably small vacancy complexes. These small vacancy complexes are often incorporated in striae during crystal growth, and are susceptible both to annihilation by oxidation induced excess self‐interstitials, and to breakup by high‐temperature preanneals. A surface proximity effect is also reported, in which oxygen in a surface zone immediately below the out‐diffusion zone precipitated out faster than in bulk.

ISSN:0021-8979    

DOI:10.1063/1.329204

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Atom‐ and carrier‐depth distributions have been measured for As channeled in the ⟨110⟩ and the ⟨100⟩ directions of Si in the energy range from 20 to 800 keV by secondary ion‐mass spectrometry and differentialC‐Vtechniques. Maximum channeled ranges in the ⟨110⟩ of Si are observed up to about 6 &mgr;m. The slopespof selected range parameters plotted versus ion energyE1are measured and used to discuss the relative roles of electronic and nuclear stopping for the channeled and random components of the depth distributions. Values of electronic stoppingSeor total stopping (electronic plus nuclear)Stare calculated for ion velocityv1= 1.5×108cm/s and values are given forkandpin the expressionSe,t=kEp1for the energy range studied. The values ofpfor the maximum ranges of As channeled in the ⟨110⟩ and ⟨100⟩ directions of Si are 0.50±0.03 and 0.54±0.04, respectively. The corresponding values ofSeare 5.43×10−14and 2.18×10−13eV cm2/atom, respectively, atv1= 1.5×108cm/s.

ISSN:0021-8979    

DOI:10.1063/1.329205

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The diffuse x‐ray scattering due to small defects in a silicon single crystal, which has been found by Yasuami, Harada, and Wakamatsu [J. Appl. Phys. 50, 6860 (1979)] has been identified as coming from a thin surface layer of the crystal. The small defects, therefore, cannot be B‐swirl defects and do not have any correlation with crystal growth methods, floating zone or Czochralski zone, and with growth direction. They are considered to be introduced during the surface polishing process and to exist in the surface layer of about 150 &mgr;m thick. For detecting such small defects, diffuse x‐ray scattering is more advantageous than the conventional rocking curve measurement.

ISSN:0021-8979    

DOI:10.1063/1.329206

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Internal friction measurements are made on deformed and hydrogenated Ni at frequencies of 2 Hz, 800 Hz, and 30 kHz over the temperature range between 4.2 and 373 K. Two kinds of relaxation peaksPdandPdHaccompanied by clear &Dgr;Meffects are commonly observed.Pdpeak is generated at low temperature only by plastic deformation in uncharged Ni. Electrolytic charging with hydrogen suppresses this peak but instead inducesPdHpeak at a temperature well abovePdpeak. On aging (outgassing) at temperatures between room temperature and 473 K,Pdfurther diminishes temporarily, but recovers to the original height thereafter; conversely,PdHfirst grows to a maximum height and then decays. These aging characteristics are related with nonuniform distributions of hydrogen in the samples. A good proportionality exists between the maximum height ofPdHand the height ofPdbefore H charging. In fully annealed samples wherePdis absent,PdHis not generated evidently by H charging. From these results, it is concluded thatPdpeak is ascribable to the dislocation relaxation peak of the Bordoni type, whilePdHpeak to the cold‐work peak involves the interaction between hydrogen atoms and dislocations.

ISSN:0021-8979    

DOI:10.1063/1.329207

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The use of Manganin gouages in shock reverberation experiments is demonstrated in three experimental configurations. In the first one we determine the Hugoniot curve for an epoxy resin, in the 0–8.7‐GPa range, by a single experiment using copper as anvil material. In the second we measure the degree of compaction of porous polyurethane from the magnitude of the second shock wave in a reverberation experiment. In the third we determine release states of shocked poly‐methyl‐methacrylate (PMMA). The results are compared to those obtained by other techniques or by the reverberation technique with quartz transducers.

ISSN:0021-8979    

DOI:10.1063/1.329208

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The transition temperatures (Tt) and heats of crystallization (&Dgr;H) ofa‐Ge,a‐Si, anda‐Ge1−xSixfilms deposited by rf sputtering have been measured by differential scanning calorimetry (DSC). BothTtand &Dgr;H(per gram) increase linearly withxin the alloy system. Overlapping exothermic multiple peaks are observed in the DSC traces ofa‐Ge anda‐Si samples prepared at high deposition rates, suggesting that multiple amorphous configurations may coexist in these materials.

ISSN:0021-8979    

DOI:10.1063/1.329209

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Experimental evidence is presented for trapping of Sb by TaC and Cu precipitates in Fe. These processes were studied during annealing at 873 K of Fe ion‐implanted with either Ta, C, and Sb, or Cu and Sb. For both precipitates the derived binding enthalpy is ∼0.4 eV when referenced to an Sb solution site in the bcc‐Fe phase. It is argued that this trapping occurs at the precipitate‐host interface, and that it is due primarily to the associated structural discontinuity. In the Fe‐Cu‐Sb alloys, trapping was accompanied by two other processes which immobilize Sb, namely, dissolution into the fcc‐Cu phase and formation of &bgr;‐Cu3Sb. The trapping effects observed in these studies are of potential significance for the control of Sb embrittlement in ferritic steels.

ISSN:0021-8979    

DOI:10.1063/1.329210

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Heteroepitaxial films of (001) oriented GaxIn1−xP(x≊0.5) deposited on GaAs buffer layers have been grown by molecular beam epitaxy (MBE). Other than dislocations threading from the substrate, 1‐&mgr;m‐thick alloy films were free of extended defects in TEM examination for a range of 300‐K misfit strains between −7×10−4and 1.4×10−3. In contrast to VPE grown GaxIn1−xP, the absence of misfit related dislocations over such a range of misfit strains is believed to result primarily from the low MBE growth temperatures (670–790 K). TEM micrographs recorded using bright‐field, two‐beam conditions showed a grainy texture on the scale of 100 A˚ which may arise from group III sublattice inhomogeneity. Similar contrast is observed in high luminescence efficiency LPE GaxIn1−xAsyP1−yand VPE Ga0.5In0.5P. The photoluminescent (PL) efficiency from nominally undoped, 1‐&mgr;m‐thick films of MBE GaxIn1−xP(x≊0.5) was generally constant across typical wafer widths of 2.5 cm having a composition span of 0.02 inx. Deviations from this behavior may have resulted from variations in the group V to group III flux ratio from layer to layer. The maximum, external PL efficiency for near band edge emission for 1‐&mgr;m‐thick layers was 1.8×10−5. This low value is not due to competing radiative transitions between 1.9 and 0.5 eV since the low temperature PL spectra consist only of two dominant, near band edge peaks whose excitation dependence suggests they are donor band and donor acceptor in nature. They are probably associated with C and Si impurities, which have been detected by PL in the GaAs buffer layer. Both the 300 and 11‐K PL linewidths of nominally undoped films are broader than expected from thermal considerations alone and may reflect group III sublattice disorder. The dispersion of the refractive index of Ga0.51In0.49P has been determined in the range 700–1700 nm.

ISSN:0021-8979    

DOI:10.1063/1.329211

出版商:AIP    

年代:1981

数据来源: AIP