摘要:

The sidegating effect in a GaAs metal–semiconductor field effect transistor is significantly suppressed by the use of a multiquantum barrier (MQB) structure as a buffer layer. The enhancement of potential barrier height of the MQB buffer layer is confirmed from the comparison with a heterostructure buffer layer device. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115073

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Chemical shifts of Si–Hx(x=1,2) species on Si surfaces obtained byexsituchemical treatment have been evaluated by high‐resolution x‐ray photoelectron spectroscopy at a take‐off angle of 5°. Optimizing the water rinse and sample loading conditions enables identification of the Si–Hxcomponents of the Si 2pcore‐level spectra, whose intensities display strong dependence on crystallographic orientation and surface treatment. NH4F‐treated Si(111) exhibits almost exclusive monohydride termination which induces a chemical shift of 250 meV relative to the bulk component. On the other hand, 4.5% HF‐treated Si(111) and 1% HF‐treated Si(100) surfaces show increased dihydride termination with an associated shift of 480 meV. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115074

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Ap‐njunction has been formed inn‐type silicon carbide (6H–SiC) by aluminum (Al) doping at room temperature using a pulsed laser doping method. A 6H–SiC substrate in [H2+(CH3)3Al] atmosphere was irradiated by an KrF excimer laser of 20 ns full width at half‐maximum. The depth profile of Al determined by secondary ion mass spectroscopy showed a rectangularlike shape with a maximum concentration of 1×1022Al/cm3. Furthermore, Al atoms were doped to a depth of about 0.05 &mgr;m from the surface. The current–voltage characteristics of thep‐njunction clearly showed the rectifying property with low leakage current. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115075

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Gold diffusion was used to understand the influence of phosphorus diffusion on defect structure of two step annealed Czochralski silicon wafers which contain oxygen related precipitates. Thanks to deep level transient spectroscopy measurements and use of relations already published, it was found that substitutional gold concentration is independent of oxygen precipitation, while phosphorus diffusion, by means of the injection of self‐interstitials in the bulk, shrinks the oxygen precipitates and increases substitutional gold concentration approximately to the solubility limit. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115076

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We report the design, growth, and characterization of an InAlP/InGaP strain‐modulated aperiodic superlattice heterobarrier (SMASH) for the enhancement of the performance of visible light‐emitting devices. These InAlP/InGaP heterostructures are grown on GaAs substrates by low‐pressure metalorganic chemical vapor deposition. Electron‐wave reflectivity calculations show that the virtual confining potential energy for conduction‐band electrons at the InAlP/InGaP interface can be increased by up to ∼660 meV by employing this novel barrier. Significant improvements in photoluminescence intensity at 300 and 4.2 K are observed from both InGaP quantum well and InGaP bulk‐layer double heterostructures utilizing the SMASH structure. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115077

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Data are presented demonstrating low‐resistance Ohmic conduction across interfaces formed by high‐temperature (750–1000 °C) compound semiconductor wafer bonding. Unipolar junctions formed by wafer bonding surfaces consisting of In0.5Ga0.5P/In0.5Ga0.5P, GaP/GaP, GaP/In0.5Ga0.5P, and In0.5Ga0.5P/GaAs are shown to exhibit low‐resistance Ohmic conduction for bothp‐ andn‐isotype junctions. The achievement of these properties is demonstrated to be critically dependent upon the crystallographic alignment of the bonded wafer surfaces, irrespective of the lattice mismatch between the surfaces. Specifically, we show that the surface orientation of the bonded surfaces must be nominally matched while simultaneously maintaining rotational alignment of the wafers. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115078

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Possible causes of a dense network of threading defects in epitaxial hexagonal GaN films grown on various substrates are discussed. We show that these defects originate at the substrate/film interface as the boundaries between differently stacked hexagonal domains, and are created by surface steps on substrates nonisomorphic with wurtzite GaN. We argue that these defects are inherent in the epitaxy of wurtzite films on nonisomorphic substrates. As a result, isomorphic substrates such as ZnO and GaN should be explored for wurtzite nitride growth. Possible effects of these defects on the properties of wurtzite nitrides are briefly discussed. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115079

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Photoluminescence studies on ‘‘as‐grown’’ as well as hydrogenated undoped AlGaAs epitaxial layers grown by metalorganic vapor phase epitaxy has been carried out to study the effective passivation of defect centers. We report the observation of defect bound excitons which are effectively passivated by hydrogenation and the preferential enhancement of excitonic features after hydrogenation. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115080

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The photoreflectance (PR) spectroscopy of &dgr;‐doped or similar structured sample has been observed to exhibit many Franz–Keldysh oscillations (FKOs). The beats are shown in the FKOs and they are attributed to the different frequencies of the FKOs of the transitions from the heavy and light holes. We have applied the fast Fourier transform on the PR spectra to separate the contributions from the heavy and light holes. The electric fields in the undoped layer can be calculated from the frequencies of heavy and light holes, respectively. The result of the heavy hole agrees well with that from the conventional FKOs fittings if the reduced mass=0.055m0is used in the conventional fittings. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115081

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The ability to grow Si1−xGexthin films on single‐crystal silicon or fused silica substrates by the pulsed excimer laser ablation from a sintered SiGe target is investigated. The stoichiometry of the deposits was found to depend essentially on the Ge enrichment of the ablated target surface. Crystalline layers were obtained for substrate temperatures higher than a threshold value depending on its nature. Finally, surfaces, nearly free from droplets, were achieved by optimizing the laser irradiation conditions. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115082

出版商:AIP    

年代:1995

数据来源: AIP