摘要:

The relaxation of heavily carbon doped GaAs, grown on (001) GaAs substrates was investigated using transmission electron microscopy and x-ray diffraction. Misfit dislocation introduction occurred only significantly above Matthews and Blakeslee’s critical thickness, with the onset of relaxation being delayed as the C concentration was increased. The resultant strain relaxation was highly anisotropic with the introduction of As-cored misfit dislocations being totally suppressed at the highest C levels, resulting in cracking of the epilayer. Locking of As-cored partial dislocations and a reduction in misfit dislocation velocity is proposed as the cause of the anisotropy and lack of relaxation. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119306

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Ultrathin (8–23 Å) silicon oxynitrides have been studied in the temperature range of 560–1000 °C in 4 Torr of NO using a sequential growth and analysis approach. X-ray photoelectron spectroscopy indicates that with increasing growth temperature and time, a bonding structure with predominantly Si–O rather than Si–N formation is favored. Simultaneously, the average volume fraction of N (N/N+O) in the dielectric decreases, as a consequence of which the N1sbinding energy increases by 0.2–0.8 eV from its initial value of 397.8 eV at a thickness of 8 Å. A correlation of the electrical characteristics of NO grown oxynitrides with nitrogen content and location has been made. A film growth mechanism that takes into account the removal of previously incorporated N by NO is also proposed. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119307

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Microwave plasma oxidation (below 200 °C) of strained Si on relaxedSi1−xGexbuffer layers inN2O ambient is reported. The electrical properties of grown oxide have been characterized using a metal-oxide-semiconductor structure. Fixed oxide charge density and mid-gap interface state density are found to be6×1010 cm−2and1.2×1011 cm−2 eV−1, respectively. The oxide on strained-Si samples has exhibited hole trapping behavior and moderately low interface state generation on constant current stressing. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119308

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The coupled modes of plasmons and LO phonons appearing in the Raman spectra of highly doped GaAs layers have been investigated in order to study the local incorporation character of Si on different crystal facets. The Si-doped GaAs layers were grown by molecular beam epitaxy on patterned GaAs (100) substrates with etched ridges forming (111)A and (111)B facets with a lateral extension of a few micrometers. The local type and concentration of free charge carriers have been determined from an analysis of the coupled-mode Raman spectra. It is shown that Si acts as a donor in the material grown on the (111)B facets and as an acceptor in the material grown on the (111)A facets. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119309

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We report on differential transmission measurements on low temperature grown (LT)-GaAs with and without applied electrical fields at different wavelengths. Electrical fields up to 100 kV/cm can be applied via an interdigitated contact structure to our LT GaAs samples which have been removed from the substrate by epitaxial lift off. In the presence of an electric field, both, the absorption bleaching due to phase space filling and field induced absorption changes due to the Franz–Keldysh effect contribute to the transmission changes. We observe an extended carrier lifetime with applied field. The response time of a biased metal–semiconductor–metal detector, therefore, exceeds the carrier life time of the substrate material. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119310

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have used cross-sectional scanning tunneling microscopy to study the atomic-scale interface structure ofInAs/Ga1−xInxSbsuperlattices grown by molecular beam epitaxy. Detailed, quantitative analysis of interface profiles obtained from constant-current images of both (110) and (11¯0) cross-sectional planes of the superlattice indicate that interfaces in the (11¯0) plane exhibit a higher degree of interface roughness than those in the (110) plane, and that theGa1−xInxSb-on-InAs interfaces are rougher than the InAs-on-Ga1−xInxSbinterfaces. The roughness data are consistent with anisotropy in interface structure arising from anisotropic island formation during growth, and in addition a growth-sequence-dependent interface asymmetry resulting from differences in interfacial bond structure between the superlattice layers. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119311

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Direct simulation Monte Carlo calculations indicate that significant differences can exist between the translational, rotational, and vibrational temperatures of molecular hydrogen under diffusion-dominated diamond chemical vapor deposition conditions. For hydrogen confined in a 1 cm gap between an activating source and a diamond substrate, the largest discrepancies between the translational and rotational temperatures ofH2occur at a pressure of approximately 2 Torr, but measurable differences persist for pressures exceeding 20 Torr. The observed trends are due to the inefficiency of intermolecular collisions at exciting the internal modes ofH2.©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119312

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have developed a high-power (5 kW) rf plasma source for nitrogen doping in ZnSe molecular beam epitaxy. Optical emission spectroscopy shows dominant atomiclike emissions around 800 nm due to excited neutral nitrogen atoms in the high power region and their intensities rapidly increase with increasing the rf power from 1 to 3 kW. The high net acceptor concentration(NA–ND)of1.2×1018 cm−3was achieved at the growth temperature of 220 °C and the activation ratio[(NA–ND)/N]as high as 60&percent;, which is the highest value so far obtained forNA–ND∼1018 cm−3.Consequently, the PL spectrum showed well-resolved deep donor-acceptor pair emissions even with highNA–ND.©1997 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.119314

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have investigated room-temperature photoreflectance (PR) spectra in Er-doped InP grown by low-pressure organometallic vapor phase epitaxy. A new feature is clearly observed at 1.31 eV, accompanied with a feature due to the bandgap transition at 1.35 eV. The new feature is attributed to a transition involving an Er trap. The transition energy is independent of both doping processing techniques and concentrations of Er in the layers. The PR spectral width of the trap transition energy described by the broadening parameter, increases linearly with the logarithm of Er concentrations. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119315

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The pure strain dependence of the chirp parameter (linewidth enhancement factor) of electroabsorption in the 1.55 &mgr;m window for strain ranging from compression to tension is studied theoretically in InGaAsP strained quantum well (QW) structures. The small-signal chirp parameter for TE polarization is evaluated from calculated electroabsorption (EA) spectra based onk⋅ptheory and their Kramers–Kro¨nig transformed refractive index changes. It is found that both compressive and tensile strain in the well layer reduce the chirp parameter. In a tensile-strained QW, almost continuously negative values irrespective of applied electric fields occur at an optimized amount of strain. The compressive-strained QW lowers the chirp parameter to nearly zero or negative values, the amount of the reduction being proportional to strain amount. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119316

出版商:AIP    

年代:1997

数据来源: AIP