摘要:

Observations of homoepitaxial growth on low-angle miscut (∼0.1°) Si(111) substrates through an overlayer of Au, together with earlier results on highly miscut Si(111) surfaces, indicate that growth in this system occurs by step flow. The growth temperatures were between 375 and 500 °C. In the optimum range of Au coverage (0.6–1.0 ML), ion channeling measurements yield at best&khgr;min=5.0&percent;, and cross-sectional transmission electron microscopy reveals stacking faults on (111) planes. Films produced under similar conditions on bare Si(111) substrates are much more defective. On the other hand, the defect density in the present films is higher than that in films grown on substrates with a higher miscut angle. The improvement in film quality resulting from the Au overlayers is attributed to an increase in the diffusion length of the Si adatoms, caused by Au passivation of the Si terraces. It is suggested that Au is more efficient than other overlayers in promoting step flow because Au passivates the Si(111) terraceswithoutpassivating the step edges. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118918

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

For a low dielectric constant intermetal dielectric application, fluorinated silicon oxide(FxSiOy)films were deposited in an electron cyclotron resonance chemical vapor deposition system, withSiH4,O2,andCF4as the reaction gases. Since theCF4is an indirect fluorinating precursor, the fluorinating mechanism resembles that of the oxide etching by a fluorocarbon plasma. Thermal stability of the incorporated fluorine (and hence, the dielectric constant) relies heavily on the deposition parameters and technologies. According to experimental results, adding Ar gas during deposition can improve the thermal stability of incorporated fluorine. Such an improvement is due to the fact that Ar sputtering enhances the removal of weakly bonded silicon fluoride on the as-deposited film surface, thereby elevating the mean bonding strength of fluoride remaining in the oxide. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118939

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

In this work ballistic electron emission microscopy was used to probe on nanometer scale the local Schottky barrier height in metal-semiconductor (MS) contacts with an intentionally inhomogeneously prepared metallization. Schottky barrier maps of heterogeneous Au/Co/ GaAs67P33(100)-Schottky contacts show areas with different barrier heights which can be correlated to different metallizations (Au or Co) at the interface. The local Schottky barrier height of the Co patches depends on their lateral extension. This result can be explained by the theory of the potential pinch-off effect in inhomogeneous MS contacts. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119203

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Using electro- and photoreflectance with a spatial resolution of≈10 &mgr;mwe have evaluated the energy of the fundamental conduction to heavy-hole (1C–1HH) quantum transition of a fabricated 0.98 &mgr;m InGaAs/GaAs/InGaPp-i-nquantum well laser structure as a function of bias and position on the laser stripe. From a comparison of the measured forward/reverse bias dependence of the1C–1HH energy with a theoretical calculation of the quantum confined Stark effect, we have been able to evaluate the built-in electric field and width of the insulating region. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118919

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We investigate island formation during heteroepitaxial growth using an atomistic model that incorporates deposition, activated diffusion, and stress relaxation. For high misfit the system naturally evolves into a state characterized by a narrow island size distribution. The simulations indicate the existence of a strain assisted kinetic mechanism responsible for the self-assembling process, involving enhanced detachment of atoms from the edge of large islands and biased adatom diffusion. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118920

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

During indiffusion of Ni atoms in silicon crystals at 950 °C from a nickel layer source, Ni–Si alloys can be formed close to the surface. Metal solubility in these alloys is higher than in silicon, which induces a marked segregation gettering of the Ni atoms which have diffused in the bulk of the wafers. Consequently, the regions of the wafers covered with the Ni layer are less contaminated than adjacent regions in which Ni atoms have also penetrated, as shown by the absence of precipitates and the higher diffusion length of minority carriers. The results suggest the existence of external self-gettering of Ni atoms by the nickel source. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118921

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

In this work, a barrier height of ∼0.7 eV is constantly observed from theIn0.53Ga0.47AsSchottky diodes, regardless of the utilization of different metals as Schottky contacts. By the addition ofPr2O3andIn2O3in the liquid phase epitaxy, a very low background impurity concentration is also obtained. The low background concentration is credited to the gettering effect from the addition of Pr and oxygen in the growth melt. The high Schottky barrier is attributed to the formation of a stable oxide layer on the surface of the epilayer, which in turn forms a metal-insulator-semiconductor structure in our Schottky diodes. The high Schottky barrier is very stable even at a high measuring temperature and was repeatedly obtained after four months of exposure to the environment. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118922

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The effect of a small amount of nitrogen incorporated in chemical vapor deposited diamond films on their electrical properties was studied. Upgrading the purity ofCH4gas from the conventional ultra-high purity to the grade with no detection of nitrogen resulted in improvement of electrical properties of the boron-doped homoepitaxial diamond films; the Hall mobility was increased by 4.3 times at the room temperature. Decrease in nitrogen concentration in the diamond films was confirmed by investigating the 2.16 eV center of cathodoluminescence induced by ion beam irradiation and subsequent annealing. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118923

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The band discontinuities between GaN and InN, as well as InGaN alloys, are key parameters for the design of nitride-based light emitters. Values reported to date are subject to large uncertainties due to strain effects at this highly mismatched interface. We have investigated the band lineups using first-principles calculations with explicit inclusion of strains and atomic relaxations at the interface. We find that the “natural” valence-band offset between unstrained InN and GaN is 0.3 eV. Prescriptions are given, including the band shifts, due to strains at a pseudomorphic interface. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118924

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have investigated spectroscopically the emergence of gain in InGaN/GaN quantum well diodes under high current injection(>kA/cm2).The spectral characteristics suggest that the electronic states responsible for blue laser action in this material are strongly influenced by the presence of microscopic crystalline disorder. ©1997 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.118925

出版商:AIP    

年代:1997

数据来源: AIP