摘要:

High‐pressure/low‐temperature plastic deformation of silicon leads to the appearance of new electron spin resonance active centers. One of them could be identified to be the pentavacancy Si‐P1, which also can be produced by irradiation. Depending on the deformation axis the defect occurs in several homologous orientations. Spin‐lattice relaxation time measurements performed on both plastically deformed and neutron‐irradiated silicon show the existence of an Orbach‐type relaxation with an activation energy of about 23 meV corresponding to the thermal excitation energy of the resonant electron into its high‐temperature state.

ISSN:0003-6951    

DOI:10.1063/1.97731

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The solid phase epitaxial regrowth of implanted phosphorus amorphized ⟨100⟩ silicon during rapid thermal annealing (RTA) in the temperature range 475–600 °C has been studied using Rutherford backscattering and channeling measurements. Within the temperature range 475–550 °C, our results show an enhancement of growth rate (Vg) by a factor of 4 when compared with values reported in literature for processing in a conventional furnace, with an activation energy of 2.7±0.2 eV. For temperatures above 550 °C, a reduction of this enhancement effect sets in, with a fall in the enhancement factor from 4 at 550 °C to about 1.5 at 600 °C. Estimation of the absolute error in temperature measurement in the RTA furnace shows that the accelerated kinetics cannot be completely explained by such errors as they are small compared to the enhancement rate. These results therefore give evidence of RTA induced enhancement of growth rate during solid phase recrystallization of implantation‐amorphized silicon.

ISSN:0003-6951    

DOI:10.1063/1.97732

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We have used reflection high‐energy electron diffraction to characterize the initial surface of misoriented Si (100) and then to follow the nucleation of GaAs. Measurement of the diffracted intensity along the length of the specular streak shows sharp structure due to an ordered array of steps. The initial surface contains monolayer steps. However, after exposing to an As4flux above 650 °C, the surface morphology changes to multilayer steps with four times the original period. In contrast, below 650 °C, surface migration is inhibited and monolayer steps are retained. Subsequent growth of GaAs on either the monolayer‐ or multilayer‐stepped surfaces yields single domain films. However, GaAs grown on the monolayer steps is misoriented toward the (111)Awhile GaAs grown on the multilayer steps is misoriented toward the (111)B.

ISSN:0003-6951    

DOI:10.1063/1.97733

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Scanning tunneling microscopy (STM) of (001) GaAs samples immersed in aqueous solutions has been used to assess the effectiveness of a standard bromine‐methanol chemomechanical polish to produce flat surfaces over length scales from 5 to 1000 nm. The STM images reveal irregular 100‐nm features coexisting with large areas of average roughness of the order of a few nanometers. The precision, stability, and reproducibility of these images suggest that immersion STM could be used to study surface chemical processes in real time.

ISSN:0003-6951    

DOI:10.1063/1.97734

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The enhanced diffusion tail of implanted boron in Si was studied using conventional furnace annealing. Surface layer stripping was applied to remove part of the sample before annealing in order to distinguish the effect of the defect‐rich surface region from the tail region on the enhanced diffusion of boron. The boron concentration profiles were obtained with secondary ion mass spectrometry (SIMS). Spreading resistance profiles were also measured to compare with the SIMS profiles. The results show that implantation‐induced damage in the surface region is responsible for the enhanced boron diffusion. Channeled boron in the tail of the implantation profile becomes activated during annealing and has little effect on the tail redistribution during annealing.

ISSN:0003-6951    

DOI:10.1063/1.97735

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We have studied the optical properties of lattice‐matched GaAs/AlxGa1−xAs and InyGa1−yAs/GaAs strained‐layer superlattices grown on Si substrates using the photoreflectance technique. These preliminary results show that good quality III‐V epilayers can be grown on Si. The experimental data were compared with calculations based on the envelope‐function approximation and fitted to the third‐derivative functional form of reflectance modulation theory.

ISSN:0003-6951    

DOI:10.1063/1.98250

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

After the EL2 absorption band at 1.2 eV is fully photoquenched [i.e., EL2 defect completely transferred from the normal (EL20) to metastable (EL2*) state] it can be partially recovered by photon excitation. This EL2*→EL20recovery exhibits peaks at 0.80 and 0.90 eV with shoulders at 0.86 and 0.94 eV. Comparison is made to the previously published photon‐induced photoconductivity recovery and the results are used to construct a modified configuration coordinate model for the EL2 defect.

ISSN:0003-6951    

DOI:10.1063/1.97736

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A new concept for a high‐speed photodetector is described which promises very low noise with avalanche gain. The detector is constructed as an integrated circuit element in the heterojunction field‐effect transistor technology and utilizes a uniquen‐nheterojunction interface formed by either metalorganic chemical vapor deposition or molecular beam epitaxy growth techniques. The degree of avalanching is controlled via an electrical third terminal.

ISSN:0003-6951    

DOI:10.1063/1.97737

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A fabrication technique for Nb‐Al2O3‐Nb Josephson tunnel junctions is described that is an alternative to the trilayer method generally used. At 4.2 K the magnitude of the low‐frequency noise in the critical currentI0of four junctions with areasAranging from 7.8 to 115 &mgr;m2was characterized byS1/2I0A1/2/I0=(14±6)pA &mgr;m/&mgr;A Hz1/2, whereSI0is the spectral density of the excess noise at 1 Hz. The noise power spectrum of one 3×3 &mgr;m2junction exhibited a Lorentzian feature associated with the emptying and filling of a single trap in the barrier. The low level of noise makes these junctions attractive for use in superconducting quantum interference devices.

ISSN:0003-6951    

DOI:10.1063/1.97738

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The rapid motion of small (∼1000 atom) gold clusters observed with atomic resolution in the electron microscope is argued to be the result of brief melting events, triggered by the Auger decay of anM‐shell vacancy created in a gold atom within the cluster. Each molten episode lasts ∼10 ps, too short for noticeable evaporation. The observed frequency of motion events is shown to be consistent with ionization cross sections for the goldMshell and the electron current densities employed. It is argued from the lack of observable evaporation that the steady‐state temperature of the clusters is ≤1100 K, well below the melting point. The model correctly predicts the cessation of motion at a particle diameter ∼8 nm, when a single Auger decay can no longer melt the cluster.

ISSN:0003-6951    

DOI:10.1063/1.97739

出版商:AIP    

年代:1987

数据来源: AIP