摘要:

Experimental evidence is presented that the effective surface recombination velocity (Seff) atp‐silicon surfaces passivated by siliconnitridefilms (fabricated in a plasma‐enhanced chemical vapor deposition system) shows an injection‐level dependence similar to the behavior of thermally oxidized silicon surfaces. Using the microwave‐detected photoconductance decay method, injection‐level dependentSeffmeasurements were taken on nitride‐passivatedp‐silicon wafers of different resistivities (1.5–3000 &OHgr; cm). The obtainedSeffvalues also show that for low‐resistivity substrates (≤2 &OHgr; cm), nitride passivation is as effective as conventional oxide passivation (and even superior at low injection levels) and furthermore offers the advantage of a less pronounced injection‐level dependence. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113443

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The growth and fabrication of high‐quality vertical distributed Bragg reflectors (DBRs) utilizing layers of InAlP and the AlAs native oxide are reported. The III–V epitaxial structures employed in this work consist of alternating layers of InAlP and AlAs grown on GaAs substrates by low‐pressure metalorganic chemical vapor deposition (MOCVD). The DBR mirrors are formed by selective lateral oxidation of the AlAs layers (H2O vapor + N2, 450 °C) resulting in a layered structure of single‐crystal InAlP and amorphous AlxOy. The oxidized vertical DBR mirrors having only 4.5 pairs exhibit high reflectivity in the 96%–99% range over a wide spectral region (&Dgr;&lgr;∼200 nm). The structural and optical properties of these DBR mirrors have been measured and show that the reflectors are of high quality. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113444

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The electrical properties of molecular beam epitaxy (MBE) grown low‐temperature GaAs (LT‐GaAs) by current transient spectroscopy (CTS) has been investigated. At least three deep traps have been observed in LT‐GaAs grown at 250 °C and annealed at 600 °C. The deepest level is dominant and has an activation energy of 0.82 eV, which is the same as that of the midgap donor, EL2. This is consistent with the activation energy of resistivity of this sample (0.77 eV), which is close to that for bulk nondoped semi‐insulating wafers. These results indicate that the Fermi level of annealed LT‐GaAs grown at 250 °C is pinned by the deep level at the midgap that is generally ascribed to AsGaantisite defects. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113445

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

This letter presents the scanning tunneling microscopy (STM) images of GaAs(001) surfaces prepared by deoxygenated and de‐ionized water (DODIW) treatment. The STM images reveal that the missing‐dimer rows and unit cells of the 2×4 structure and atomic‐layer steps of Ga–As clearly appear after heating the samples above 500 °C in an ultrahigh vacuum. These experimental results suggest the DODIW treatment can attain atomically flat GaAs(001) surface. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113446

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Internal gettering efficiencies and stabilities of high and low carbon doped silicon have been compared with standard and ramped annealing conditions. The gettering efficiency of low carbon silicon has been found to be greatly enhanced with ramped annealing by creating a high concentration of oxygen precipitates and related defects. This ramped low carbon material and both the standard and ramped high carbon materials have a greatly enhanced oxygen precipitation rate, relative to the standard low carbon standard anneal. However, the high carbon material’s gettering efficiency and stability are low, compared to the ramped low carbon material, due to a reduction of the oxygen precipitate’s strain field and concentration of related defects. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113447

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We report experimental results from an erbium‐doped gallium phosphide microdisk resonator pumped by a Ti‐sapphire laser at 980 nm. Fabrication and characterization of the microdisk resonator are discussed. Enhanced Er+3intra‐4f‐shell photoluminescence was observed in the microdisk resonator due to microcavity effect and compared to a thin film sample. At low pumping power intensity, the photoluminescence from erbium‐doped gallium phosphide microdisks is an order stronger than that from a thin film sample. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113448

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Si‐doped (211)A and (311)A GaAs samples grown by molecular beam epitaxy (MBE) with various growth As pressures have been studied. Hall effect measurements have revealed that the doping changes fromptontype by increasing the As pressure. The transition As pressure is lower for the (211)A than for the (311)A surfaces. Photoluminescence measurements have shown that by increasing the As pressure, arsenic vacancy defects are changed into pairs of Ga vacancy and Ga antisite defects. These results are explained by considering the orientation dependence of the surface bonding and the kinetics of the MBE growth process. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113449

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The ability to determine structural and compositional information from the sub‐surface region of a semiconductor material has been demonstrated using a new time‐of‐flight medium energy ion scattering spectroscopy (ToF‐MEISS) system. A series of silicon–silicon/germanium (Si/Si1−xGex) heterostructure and multilayer samples, grown using both solid source molecular beam epitaxy (MBE) and gas source chemical vapor deposition (CVD) on Si(100) substrates, have been investigated. These data indicate that each individual layer of Si1−xGex(x∼0.22) in both two‐ and three‐period samples, can be uniquely identified with a resolution of approximately 3 nm. A comparison of MBE and CVD grown samples has also been made using layers with similar structures and composition. The total Ge content of each sample was confirmed using conventional Rutherford backscattering spectrometry. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113450

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The conduction band discontinuities in Ga0.5In0.5P‐AlxGa0.5−xIn0.5P heterojunctions, lattice matched to GaAs and grown by molecular beam epitaxy, were measured by internal photoemission techniques at room temperature over the whole compositional range. The discontinuity is found to vary linearly inxas (0.59x)eV forx≤0.30 and as (−0.18x+0.23)eV forx≳0.30, whereas the inferred valence band discontinuity (band‐gap difference minus the conduction band discontinuity) varies as (0.61x)eV. The direct–indirect gap crossover composition in AlxGa0.5−xIn0.5P is found to be close tox≊0.3. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113451

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The depth distribution of open‐volume defects has been studied in Si(100) crystals grown by molecular beam epitaxy at 300 °C by the variable‐energy monoenergetic positron beam technique combined with well‐controlled chemical etching. This procedure gave a 10 nm depth resolution which is a significant improvement over the inherent depth resolving power of the positron beam technique. The epitaxial layer was found to grow defect‐free up to 80 nm, from the interface, where small vacancy clusters, larger than divacancies, appear. The defect density then sharply increases toward the film surface. The result clearly shows that the nucleation of small open‐volume defects is a precursor state to the breakdown of epitaxy and to the evolution of an amorphous film. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113452

出版商:AIP    

年代:1995

数据来源: AIP