摘要:

In an earlier paper, classical and weak degeneracy, with the activity parameterrbetween 0 and 1, are investigated. In this paper, intermediate and strong degeneracy, withr>1, are studied. Coefficients for the Joyce–Dixon‐type series are calculated for bosons as well as fermions in one, two, and three dimensions, for either nonrelativistic or ultrarelativistic particles. The theory is applied to the electrons and Cooper pairs in mercury at four temperatures.

ISSN:0021-8979    

DOI:10.1063/1.341958

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

We have studied the solid phase epitaxial regrowth (SPER) of implantation [31P+,11B+(73Ge+preamorphized)] amorphized silicon in the temperature range 500–600 °C induced by rapid thermal annealing (RTA), using Rutherford backscattering (RBS) and channeling measurements. Our results show rate enhancements (&bartil;3.5–6.5) of the velocities of regrowth in all cases studied with respect to values reported in the literature for furnace‐induced epitaxy. The measured SPER activation energies (2.7 and 2.6 eV for31P+and11B+implantations, respectively) while being comparable to literature reported values, were nevertheless higher than the energy required for the activation of these dopants, &bartil;1.55–2.45 eV. Also, the ratioVB/VP(velocity of regrowth in the presence of boron with respect to phosphorus) gives a value of approximately 3 in both RTA and furnace‐induced kinetics. These results are explained by a model which takes into account the role of electrically active interfacial defect sites during SPER.

ISSN:0021-8979    

DOI:10.1063/1.341959

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Ion‐beam mixing at an Fe:metallic glass (Fe67Co18B14Si1) interface is studied by employing the technique of conversion electron Mo¨ssbauer spectroscopy (CEMS). A 230‐A˚‐thick overlayer of iron (enriched to 33% in the concentration of57Fe Mo¨ssbauer isotope) was deposited on the shiny surface of metallic glass and such composites were bombarded with 100‐keV Kr+ions at dose values in the range between 1×1015and 2×1016ions/cm2. The transformations in the local atomic arrangements across the interface were investigated by monitoring the changes in the hyperfine‐interaction parameters. It is shown that mixing leads to significant changes in the composition, in the vicinity of the interface as a function of the ion dose. At low dose (1×1015ions/cm2) the local atomic coordination is found to be rich in the transition‐metal concentration, while at a higher dose (2×1016ions/cm2) it is observed to be rich in the boron concentration. Interestingly, at an intermediate dose 1×1016ions/cm2the composite near the interface region partially crystallizes and this structural state is found to revert back to the amorphous state upon thermal annealing at 300 °C. The observations made on the basis of CEMS are well supported by x‐ray diffraction measurements.

ISSN:0021-8979    

DOI:10.1063/1.341960

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Thin films of &agr;Rh2As were grown on top of GaAs (001) in a molecular‐beam epitaxy system by codeposition of rhodium and arsenic from separate sources. &agr;Rh2As is a good metal with a resistivity equal to 20 &mgr;&OHgr; cm, suitable for electronic applications. The holes, the only type of carriers, have a concentration equal to 2.5×1022cm−3, i.e., a value of the same order of magnitude as that of the best silicides. However, in spite of several features common to &agr;Rh2As and GaAs (symmetry, almost equivalent unit‐cell constant, and fcc As sublattices), the epitaxial arrangement [100](011)&agr;Rh2As//[110](001)GaAs mainly prevails instead of the expected simple unrotated relationship [100](001)&agr;Rh2As//[100](001)GaAs. This points out that the achievement of the minimum lattice mismatch is not always the driving force for the epitaxy. In agreement with the ternary phase diagram Rh‐Ga‐As, the (polycrystalline &agr;Rh2As)/GaAs system interacts above 400 °C and leads to the formation of the binary compounds RhGa and RhAs2.

ISSN:0021-8979    

DOI:10.1063/1.341961

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Spectroscopic ellipsometry and x‐ray diffraction measurements have been used to obtain structural information on hydrogenated amorphous and microcrystalline silicon thin films. The films were deposited onto quartz substrates from a microwave plasma in SiH4/H2gas mixture. For ellipsometric data analysis, the films were modeled as multilayer structures with the dielectric response of each layer calculated as a function of the amorphous, crystallite, and void volume fractions through an effective‐medium approximation. Results indicate that the transition from amorphous‐to‐microcrystalline films is accompanied by a reduction in the material density and a significant increase in the surface roughness overlayer. X‐ray diffraction measurements estimate a higher volume fraction of crystallites as compared to that obtained from optical data.

ISSN:0021-8979    

DOI:10.1063/1.341962

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Using metalorganic vapor‐phase epitaxy, zinc selenide films are grown on GaAs surfaces of three different orientations: (100), (100) tilted 2° off toward ⟨011⟩, and (100) tilted 5° off toward ⟨011⟩. The properties of these epilayers are determined by x‐ray diffraction and photoluminescence. There is remarkable difference in lattice relaxation mechanism between exact (100) case and 5° off, a part of lattice mismatch stress in the ZnSe layer on 5° off substrate is relaxed by lattice inclination. This inclination prevents the generation of defects and dislocations. Photoluminescence properties are also improved by using the tilted substrates. Strong near‐band‐edge emission and weak deep‐level emissions such asY0,S, andSAlines compared with those grown on exact (100) substrates are observed.

ISSN:0021-8979    

DOI:10.1063/1.341963

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Estimates of the effective deposition probability for plasma‐deposited amorphous silicon (a‐Si:H) films were obtained from computer simulations using a Monte Carlo technique. Randomized scattering events are tracked to simulate the deposition ofa‐Si:H along etched trenches under a metallic shadow mask. The resulting film thickness profiles are consistent with scanning electron micrographs obtained from step coverage experiments. Device quality materials tend to have effective deposition probabilities lower than 0.01 and are associated with CVD‐like deposition involving SiH3radicals. Defective materials are found to have deposition probabilities near unity and are associated with a PVD‐like process involving SiH and SiH2radicals.

ISSN:0021-8979    

DOI:10.1063/1.342509

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Homoepitaxial film growth maintaining primary surface structures of Si substrates was investigated by using the reactive ion beam deposition method proposed recently. This method uses ionized species of reactive SiH4gas controlled in the low‐energy region of less than 500 eV. At 100–150 eV, homoepitaxial film growth on Si(111) and Si(100) maintaining their primary 7×7 and two‐domain 2×1 surface structures, respectively, can be achieved at the low temperatures of 650 and 600 °C, respectively. In addition, oxygen impurities on substrate surfaces, due to imperfect substrate cleaning and recontamination caused by residual gases in a growth chamber before film growth, were successfully reduced at 600 °C by irradiating the 100‐eV controlled ionized species onto them.

ISSN:0021-8979    

DOI:10.1063/1.341964

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

New characterization data are presented for the deep‐level defects observed in photoluminescence (PL) spectra of InGaAs near 0.1 eV within the band gap. The literature regarding these defects is summarized and compared to the results of this study. Defects are seen to be present in In‐rich, Ga‐rich, and lattice‐matched In1−xGaxAs/InP epilayers. The PL spectra vary depending on alloy composition and crystal growth conditions. PL spectra at 77 K for 0.46<x<0.50 and input laser powers of 9–18 W/cm2are given for material grown by organometallic vapor phase epitaxy. Hall mobility and Auger electron specroscopy data are also give for these epilayers. The cause of the defects is unknown, but it is not InP substrate doping or growth impurities. Imperfect arsenic incorporation may be involved, as evidenced by the dependence of PL spectra on growth conditions.

ISSN:0021-8979    

DOI:10.1063/1.341965

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Ana‐Si:H sample was soaked by AM1 light at 300 K (stateB1) and 100 K (stateB2), respectively. An annealing activation energy of 1.2 eV was found for the metastable subband‐gap absorption. However, for the recovery of the mobility‐lifetime product, &mgr;&tgr;, an activation energy of 0.9 eV was found for both statesB1 andB2. The capture cross section of the recombination centers was estimated. It is suggested that the degradation in the &mgr;&tgr; product is due to the creation of new recombination centers near the dark Fermi level with at least an eight times larger capture cross section than that of neutral dangling bonds.

ISSN:0021-8979    

DOI:10.1063/1.341966

出版商:AIP    

年代:1988

数据来源: AIP