摘要:

The electrical properties of InP insulator interface were improved by using a new native oxide between gate insulator and the semiconductor. This phosphorus‐rich oxide identified as In(PO3)ypolyphosphate was grown anodically. Capacitance‐voltage measurements on this metal‐insulator‐semiconductor structure yielded an interface state density as low as 4×1010cm−2eV−1and were nearly free of hysteresis in the depletion and accumulation region.

ISSN:0003-6951    

DOI:10.1063/1.97386

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A technique of high voltage electron beam lithography and BCl3/Ar reactive ion etching for laterally patterning GaAs/Al0.3Ga0.7As multiple quantum wells is described. The resulting structures were analyzed using scanning electron microscopy and a novel reflection electron microscopy technique, and their geometries are shown. Narrow columns 40 nm in diameter etched 230 nm through the quantum wells were reproducibly fabricated.

ISSN:0003-6951    

DOI:10.1063/1.97387

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Microstructural studies of Si‐Si interfaces grown by molecular beam epitaxy reveal pockets of oxygen‐rich material for certain substrate preparation conditions. For Czochralski substrates which are cleaned using an argon ion sputtering technique, a high density (about 1011/cm2) of oxygen‐rich pockets about 30 A˚ in size is observed using cross‐sectional transmission electron microscopy and x‐ray microanalysis for short (less than about 15 s) sputtering times. For longer sputtering times, no significant defect density is observed. Post‐deposition thermal annealing causes a dramatic increase in the density of oxygen‐rich defects, and it is suggested that this is due to trapping of oxygen which has diffused from the bulk of the substrate wafer. For (100) interfaces, no significant dislocation activity is associated with the defects, even for densities up to 1012/cm2. On (111) interfaces, however, a large planar fault density is observed. Ramifications for silicon homoepitaxy are discussed.

ISSN:0003-6951    

DOI:10.1063/1.97388

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The morphology and crystal quality of CdTe grown on InSb substrates are shown to be critically dependent on the pregrowth stabilization procedure to which the substrate has been subjected. It is shown that layer growth on a dimethylcadmium stabilized InSb substrate results in CdTe layers with a large number of hillocks whereas growth on a diethyltelluride stabilized substrate results in a smooth morphology. These hillocks are initiated by the reaction of dimethylcadmium with the InSb surface; alloys of In‐Cd‐Sb formed at the interface result in deterioration of the layer morphology. This problem can be avoided by growth on a diethyltelluride stabilized surface, at temperatures below 400 °C. Improvement in the layer quality by use of this technique is illustrated by a study of the photoluminescence spectra (PL) of CdTe grown by these two methods. Layers have been grown with a band‐edge PL peak having a full width half‐maximum of 2.1 meV at 12 K. To our knowledge, this is the lowest value for epitaxial layers of CdTe on InSb grown by any technique at the present time.

ISSN:0003-6951    

DOI:10.1063/1.97389

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Resonant tunneling has been demonstrated through a double barrier, single quantum well HgTe/Hg1−xCdxTe heterostructure for the first time. Negative differential resistance is observable at room temperature, exhibiting a 1.4:1 peak to valley tunnel current ratio. The observation provides direct evidence for the existence of the proposed intrinsic interface state.

ISSN:0003-6951    

DOI:10.1063/1.97390

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We find that two paramagnetic ‘‘trivalent silicon’’ centers appear to be responsible for damage resulting from Fowler–Nordheim injection of electrons into thermal oxides on silicon.

ISSN:0003-6951    

DOI:10.1063/1.97391

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We have found a long‐lived emission at low temperatures in AlAs/GaAs superlattices with approximately equal thicknesses of AlAs and GaAs and with periods in the range 18–60 A˚. The emission shows the nonexponential time decay characteristic of an indirect exciton made allowed by disorder. The exciton is found to be at the zone boundary, and to consist of a &Ggr; hole localized in the GaAs and an AlAsX‐point electron. The disorder is at the AlAs‐GaAs interfaces. There is no ‘‘camel’s back’’ in the exciton dispersion.

ISSN:0003-6951    

DOI:10.1063/1.97392

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A three‐crystal geometry has been used for high‐resolution x‐ray diffraction (XRD) along with lattice imaging transmission electron microscopy (TEM) to study two high‐quality InGaAs/InP multiquantum well structures grown on (100) InP. These superlattices were prepared by gas‐source molecular beam epitaxy using a computer controlled system and were found to have excellent optical properties. Cross‐section TEM and the presence of sharp satellite reflections in the XRD profiles demonstrate very smooth interfaces with well‐defined modulated structures which could be derived from a kinematic XRD step model. For one of these superlattices, excellent agreement between the step model and the measurements is obtained when the model assumes that each period consists only of the well and the barrier with ideally sharp interfaces. For the other superlattice an additional approximately 9‐A˚‐thick layer of approximate composition In0.47Ga0.53As0.985P0.015had to be assumed on one side of each quantum well. This additional layer is attributed to substitution of ambient P for 1.5 at. % of the As during growth interruption and is easily eliminated. The comparison of these two structures demonstrates the extreme sensitivity of the high‐resolution XRD method in conjunction with the step model to study very small modifications in superlattice characteristics.

ISSN:0003-6951    

DOI:10.1063/1.97393

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Alloys of Nb73Al12Si14.5B0.5were rapidly quenched using the melt spinning technique to form fine amorphous ribbons. These were then annealed intoA‐15 tapes with a variety of grain sizes. The smaller the grain was the more flexible the tape and the higher the critical current densityJc. The best results were obtained for a tape with a grain size of 15 nm; it could be bent to a diameter of 1 mm without breaking and it had aJcof 3.3×1010A/m2at a magnetic field of 20 T.

ISSN:0003-6951    

DOI:10.1063/1.97394

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Magnetic CoCr films deposited on fused quartz substrates were prepared by the dual‐gun magnetron co‐sputtering technique. The cross‐section transmission electron microscopy studies showed the establishment of a textured columnar structure of the hcp CoCr films. Furthermore, the columnar grains were found to nucleate at the surface of the substrates and grow with thecaxis parallel to the film‐normal direction. No initial layer of randomly oriented small equiaxed grains was observed.

ISSN:0003-6951    

DOI:10.1063/1.97395

出版商:AIP    

年代:1986

数据来源: AIP