摘要:

High quality epitaxial thin films of CoSi2(110) are grown for the first time on Si(110) surfaces using UHV template methods. Utilization of thin (10–15 A˚) room‐temperature deposits, followed by annealing, eliminates the role of long‐range diffusion during the reaction to CoSi2and produces epitaxial thin films with a single, coherent orientation. These thin epitaxial films can then be used as templates for further homoepitaxial growth of silicide. The thicker films are also of a single epitaxial orientation and exhibit &khgr;min’s as low as 5% in Rutherford backscattering. Misfit in two orthogonal directions is taken up by two distinct sets of interfacial defects which appear to have different critical thicknesses.

ISSN:0003-6951    

DOI:10.1063/1.102110

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Low‐energy electron diffraction intensity from crystallized Si film after solid phase epitaxial growth of its amorphous phase was measured. The intensity profile always shows a formation of 7×7 reconstructed structure, and the intensityIdepends on the thickness of the amorphous Si film,d: the value ofIfrom the crystallized film withd<30 A˚ is the same as that from the 7×7 reconstructed Si (111) substrate;Idecreases exponentially with the increase ofd(30 A˚<d<200 A˚). The change ofIis discussed from the viewpoint of the crystallization of the amorphous film composed of strongly distorted microcrystalline‐like grains which have a uniform orientation due to the proximity effect of the Si (111) substrate.

ISSN:0003-6951    

DOI:10.1063/1.102111

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The initial heteroepitaxial growth and structure of thin CdS layers on GaAs has been studied by conventional and high‐resolution transmission electron microscopy. The work highlights the dependence of CdS crystal type on GaAs substrate orientation. Wurtzite‐structure CdS is formed on (111)AGaAs and it is found to relieve misfit stresses by the introduction of interfacial defects, often associated with steps at the interface. Sphalerite‐structure CdS is produced by initial growth on (001)GaAs and, in this case, misfit stresses are more slowly relieved, first with the formation of an asymmetrical array of interfacial dislocations and inclined stacking faults.

ISSN:0003-6951    

DOI:10.1063/1.102114

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

High‐resolution photothermal ionization spectroscopy has been performed onn‐type high‐purity silicon crystals. Two new shallow donors with binding energies of 36.61 and 36.97 meV, respectively, are observed for the first time, in addition to lithium (Li), lithium‐oxygen complex [D(Li,O)], phosphorus (P), and arsenic (As) donors. These new shallow donors show similar spectral features to Li,D(Li,O), P, and As, which implies that they are also hydrogenic shallow donors. These new complex centers are probably generated during crystal growth. In addition, previously unresolved transitions related to very high excited states of phosphorus as well as the above‐mentioned new shallow donors, have also been observed.

ISSN:0003-6951    

DOI:10.1063/1.102090

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Epilayers of the previously hypothetical zinc‐blende MnTe have been grown by molecular beam epitaxy. Epitaxial layers (0.5 &mgr;m thick) of MnTe were characterized using x‐ray diffraction and transmission electron microscopy; optical reflectance measurements indicate a band gap of ∼3.2 eV. A series of strained single quantum well structures was fabricated with zinc‐blende MnTe forming the barrier to CdTe quantum well regions; photoluminescence spectra indicate optical transitions corresponding to strong electron and hole confinement.

ISSN:0003-6951    

DOI:10.1063/1.102091

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Enhanced incorporation of Si is observed in the metalorganic chemical vapor deposition of homoepitaxial GaAs layers, grown in the presence of Si substrates placed adjacent to the GaAs substrates in the reactor. The electron concentrations of the GaAs layers are a function of the proximity to the Si substrates and the growth temperature, and do not appear to depend on the location of the Si substrates relative to the flow direction of the carrier gases and the type of reactor used for the growth, i.e., horizontal or vertical. Reduction in electron concentrations is observed when Si substrates are covered with passivating layers of either SiO2or Si3N4. These results provide evidence of a gas phase reaction and transport of Si to the growing GaAs layers.

ISSN:0003-6951    

DOI:10.1063/1.102092

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The performance of the GaAs/AlGaAs superlattice as an infrared detecting material is modeled as a function of temperature for two cutoff wavelengths, namely, 8.3 and 10.0 &mgr;m. The results are compared with HgCdTe, the present industry standard material for infrared systems. The limiting performance of the GaAs/AlGaAs materials system is found to be orders of magnitude below that of HgCdTe for any specific cutoff wavelength and operating temperature.

ISSN:0003-6951    

DOI:10.1063/1.102093

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

An energy model has been used to calculate the minimum critical thickness in strained‐layer superlattices that is required to block threading dislocations. The model calculates the total change in the system energy that results from the presence of a bent dislocation segment at the strained interface. The calculations show that a threading dislocation has to overcome an energy barrier before gliding along the strained‐layer interface becomes favorable. The model predicts that the process of blocking threading dislocations by strained‐layer structures can be thermally activated.

ISSN:0003-6951    

DOI:10.1063/1.102094

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

GaInP material has been used as a high‐gap semiconductor on InP to fabricate Schottky diodes. The experimental results show that the devices exhibit good electrical properties when the ternary strained layer is below the critical thickness. The best device is obtained with a gallium composition of 100% and a GaP thickness of 11 A˚, and exhibits a barrier height of 0.8 eV, an ideality factor of 1.1, and a reverse current of 0.1 nA at −1 V. A high electron mobility transistor has been fabricated on an InP substrate by molecular beam epitaxy using a high‐gap GaInP material, and a transconductance of 300 mS/mm has been measured on a device of 1.3 &mgr;m gate length.

ISSN:0003-6951    

DOI:10.1063/1.102075

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Persistent photoconductivity in copper‐compensated, silicon‐doped semi‐insulating gallium arsenide with a time constant as large as 30 &mgr;s has been excited by sub‐band‐gap laser radiation of photon energy greater than 1 eV. This photoconductivity has been quenched on a nanosecond time scale by laser radiation of photon energy less than 1 eV. The proven ability to turn the switch conductance on and off on command, and to scale the switch to high power could make this semiconductor material the basis of an optically controlled pulsed‐power closing and opening switch.

ISSN:0003-6951    

DOI:10.1063/1.102076

出版商:AIP    

年代:1989

数据来源: AIP