摘要:

Raman scattering by localized vibrational modes and plasmons has been used to characterize heavilyp‐ andn‐type silicon‐doped (311)AGaAs layers grown by molecular beam epitaxy. Consistent with the doping character,p‐type samples show two modes associated with Si(As) and the complex defect Si‐X. Acceptor‐related lines were not observed inn‐type samples, an indication that compensation levels in the layers are very low. The results are discussed in relation to growth conditions on (311)Asurfaces.

ISSN:0021-8979    

DOI:10.1063/1.352131

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Synthesis of YBa2Cu3O7−&dgr;(YBCO) has been achieved using laser ablation of separate oxide targets YBa2Oxand CuO, as well as Y2Cu2O5and BaCuO2. Results obtained using two synchronized lasers to ablate from the two targets show that high quality epitaxial YBCO films can be obtained independent of the laser pulse delay settings. The facile formation of the YBCO phase, irrespective of the nature of the reacting precursors, points to its high thermodynamic stability under conditions used forinsitugrowth of films.

ISSN:0021-8979    

DOI:10.1063/1.352132

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Generalization of a previously given expression dealing with processes in which temperature and electric field are simultaneously varied is proposed in order to include also susceptibility changes.

ISSN:0021-8979    

DOI:10.1063/1.352134

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

It is demonstrated that electromigration testing needs to be performed in structures that reflect use conditions, such as when there is a flux divergence as provided by the W stud‐Al(Cu) interface rather than in a simple planar structure. The Al(Cu)/W interface has been investigated using both drift velocity and resistometric techniques with pure Al, Al(0.5 wt. % Cu) and Al(2 wt. % Cu) lines on W studs for interlevel connections. It is shown that the mass depletion can be correlated to the resistance change and electromigration failure in line/stud chains. A new effect is demonstrated in that a critical length of Al has to be depleted on Cu before the Al can migrate; when such migration starts the Al catches up with the Cu rich region, leading to slower motion and the production of extrusions which will also cause failures by shorting to adjacent lines.

ISSN:0021-8979    

DOI:10.1063/1.352335

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Intrinsic bistability in a resonant tunneling diode has been investigated theoretically using a modified resonant tunneling model. A self‐consistent solution including feedback of charges in the quantum well is found through an iterative method, where the stable and unstable solutions can be easily identified. The intrinsic bistability corresponds to the existence of two stable solutions. We find that scattering will reduce the intrinsic bistability or completely eliminate it, even for a large current peak‐to‐valley ratio (about 19).

ISSN:0021-8979    

DOI:10.1063/1.352135

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The formation of titanium silicides on Si implanted with different BF2+dosages has been studied by secondary ion mass spectrometry and transmission electron microscopy measurements. The thickness of the silicide layer formed in the temperature ranging from 600 to 800 °C has been investigated as a function of the implanted BF2+dosage up to 1×1016cm−2. Annealing at 700 °C results in conversion of the titanium film into predominantly C49 TiSi2, and most of it is transformed into the C54 phase at 800 °C or higher, resulting in a lower sheet resistance (16 &mgr;&OHgr; cm). The titanium silicide thickness formed after the rapid thermal annealing (RTA) treatment depends on the implanted BF2+dosage, caused by the native oxide enhanced by increased damage. Boron is redistributed into the silicide layer up to the solid solubility limit during annealing, leading to an accumulation at the silicide/silicon interface. The lowest contact resistance (with a size of 0.7 &mgr;m×0.7 &mgr;m) of 35 &OHgr; is obtained at the annealing temperature of 700 °C.

ISSN:0021-8979    

DOI:10.1063/1.352136

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

A new and very simple method is presented for calculating exciton binding energies in quantum confined semiconductor structures. The aim of the model calculation, which is developed in the framework of the fractional‐dimensional space, is not to compete with the very advanced ones already proposed but, on the contrary, to avoid tedious and expensive calculations to obtain, with a good accuracy, the exciton binding energy in most of the confined structures. Furthermore, in the cases where the 1sand 2stransition energies can be experimentally measured, the method permits one to obtain the exciton binding energy without any hypothesis nor calculation.

ISSN:0021-8979    

DOI:10.1063/1.352137

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The magnitude of carrier depletion at the interface between molecular beam epitaxial GaAs and a GaAs substrate is shown to depend upon the length of exposure to ultraviolet ozone radiation. In particular, as the ozone exposure time increases, the interfacial carbon concentration and loss of carriers at the interface decrease. The data suggest a relationship between electrically measured carrier depletion and the impurity species, carbon and silicon, at the interface.

ISSN:0021-8979    

DOI:10.1063/1.352138

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The method of open circuit thermally stimulated current (TSC) measured in open circuit to determine the spatial charge centroid location in a nonmetalized polymer film is presented in this paper. By performing open circuit TSC together with the measurement of the surface potential of the sample, we can calculate the location of charge centroid in dielectrics. The charge centroid in charged polyethyleneterephthalate film (50‐&mgr;m thick) measured 1.9±0.3 &mgr;m from the upper surface.

ISSN:0021-8979    

DOI:10.1063/1.352360

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

We report growth of (InAs)1(AlAs)1and (InAs)2(AlAs)2strained layer superlattices by migration enhanced epitaxy. The samples were grown on InP (001) substrates and characterized by Raman spectroscopy, x‐ray diffraction, and transmission electron microscopy. Satellite peaks in the x‐ray data confirm the intended periodicity and indicate the presence of some disorder in the monolayer sample. The energies of the zone folded and quantum confined optic phonons are in reasonable agreement with calculations based on one‐dimensional elastic continuum and linear chain models.

ISSN:0021-8979    

DOI:10.1063/1.352139

出版商:AIP    

年代:1992

数据来源: AIP