摘要:

Using Vickers indentation method, plastic deformation (Ef) is suggested to be a convenient measurement to determine the ductility (brittleness) of brittle new materials. It was found thatEfis related empirically toKICandGICthrough a logarithmic linear relationship.

ISSN:0003-6951    

DOI:10.1063/1.105018

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report, for the first time, the direct write laser patterning of highly conductive Al from a liquid precursor, triisobutylaluminum (TIBA). Al wires were written on Si with a scanned Ar+laser from liquid TIBA at speeds of up to several mm/s. Wires 3 &mgr;m wide by 1 &mgr;m high with a resistivity of 5.6 &mgr;&OHgr; cm were routinely achievable.

ISSN:0003-6951    

DOI:10.1063/1.105019

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The lateral variation of the emission energy of GaAs masklessly grown on V‐grooved Si is imaged with cathodoluminescence wavelength imaging. This newly developed unique experimental approach allows, for the first time, to directly visualize and quantify the extreme homogeneity of this novel growth mode and the lateral variation of Si impurity incorporation in such semiconductor microstructures. It represents an essential characterization tool for micropatterned optoelectronic monolithic integrated circuits.

ISSN:0003-6951    

DOI:10.1063/1.105020

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Thermally stable low‐resistance ohmic contacts ton‐type GaAs incorporating a very thin layer of Au in conjunction with a layered Ni/Ge/W structure are reported. A minimum contact resistance of 0.16 &OHgr; mm was obtained for contacts annealed at ∼650 °C. The contact resistance was ∼0.3 &OHgr; mn after thermal stressing at 400 °C for 20 h. Cross‐sectional transmission electron microscopy reveals a uniformly reacted layer only ∼34 nm deep, making these contacts significantly shallower and more homogeneous than eutectic‐based AuGeNi contacts. X‐ray diffraction shows the presence of NiGe, &bgr;‐AuGa, and W phases in the reacted contacts. The volume fraction of the low melting point &bgr;‐AuGa phase is considerably reduced from that reported for eutectic‐based AuGeNi contacts. This, along with the presence of the high melting point NiGe compound, explains in part the improved thermal stability and morphology of the low Au content ohmic contacts.

ISSN:0003-6951    

DOI:10.1063/1.105021

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Selective epitaxy of GexSi1−xin an ultrahigh‐vacuum chemical vapor deposition reactor from SiH4and GeH4/H2is reported for the first time. Growth is performed at 600 °C on patterned wafers after an 800 °C bake which provides a clean silicon surface. Selective growth is maintained during a short incubation time. GeH4/H2is found to increase the incubation time and the growth rate improving selectivity. Diodes fabricated from selectively grown films demonstrate high material and film/oxide interface quality.

ISSN:0003-6951    

DOI:10.1063/1.104998

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Oxygen content in the bulk of Czochralski silicon was analyzed by using micro‐Fourier transform infrared spectroscopy in a transversal wafer cross‐section configuration. This technique locally distinguishes between interstitial oxygen and oxygen precipitates in wafers used as substrates for epitaxial layer growth. Systematic measurements performed in the 5000–700 cm−1wavenumber range clearly indicate the presence of oxygen microprecipitates in the bulk of the processed silicon wafers. Quantitative determination of oxygen precipitate density is reported and compared with the measured interstitial oxygen concentration.

ISSN:0003-6951    

DOI:10.1063/1.104999

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Si(100) wafers have been implanted with 50 keV Co ions at elevated substrate temperatures (320 °C) in the dose range 7.8×1014–7.8×1016at. cm−2. A comparison is made between channeled (along the Si ⟨100⟩ surface normal) and random (tilted by 7°) implantations. Co depth distributions are measured with secondary‐ion mass spectrometry and compared tomarloweandtrimsimulations. Annealed samples are characterized by Rutherford backscattering spectrometry and transmission electron microscopy. Our data indicate that for channeled implantations the sputtering effect is strongly reduced as compared to random implantations. Also, the average penetration depth is increased by about 20%. As a consequence, annealing of our high‐dose implanted samples yields either a discontinuous surface silicide layer (random case) or a pinhole‐free buried silicide layer (channeled case).

ISSN:0003-6951    

DOI:10.1063/1.105000

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Tunneling spectroscopy of ultrathin (1.5 nm thick) SiO2on degenerate Si structures and of hydrogen‐terminated Si surfaces is studied with scanning tunneling microscopy (STM) in an air ambient. Two kinds of tunneling spectra, i.e., normal‐site and defect‐site spectra, are observed for the oxide samples depending on measuring sites, while only the normal‐site spectra are observed for H‐terminated surfaces. The normal‐site spectra strongly depend on dopant types and reflect bulk band structures of Si. The defect‐site spectra show negative differential resistance (NDR) and the defect sites are identified on STM images as depressed areas. The origin of the NDR is ascribed to resonant tunneling through localized defects in the oxide.

ISSN:0003-6951    

DOI:10.1063/1.105238

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The initial stage of epitaxial growth of GaP on Si by low‐pressure metalorganic chemical vapor deposition was characterized by transmission electron microscopy. The growth mode changes from three‐dimensional to two‐dimensional with increasing V/III ratio. GaP on Si grown at a low V/III ratio of 800 contains many dislocations, stacking faults, and microtwins; however, a significant reduction in the density of these defects is observed in GaP grown at high V/III ratio of 3200.

ISSN:0003-6951    

DOI:10.1063/1.104975

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The insertion of few AlAs monolayers at the interfaces between a GaAs quantum well and (Al,Ga)As barriers gives rise to a new type of structure which is well described as a double‐barrier quantum well. It is shown that only one or two AlAs monolayers are sufficient to significantly increase the confinement energies. Our results are discussed in the light of low‐temperature photoluminescence experiments and are well described in the framework of numerical calculations based on the envelope function formalism.

ISSN:0003-6951    

DOI:10.1063/1.104976

出版商:AIP    

年代:1991

数据来源: AIP