摘要:

The effect of strains on the local crystallographic symmetry and structure of a Si/GexSi1−xmodel heterostructure grown on a (100) silicon substate was studied using convergent beam electron diffraction techniques and a cross‐sectional specimen geometry. The alloy layers are seen to distort into relaxed tetragonal and monoclinic structures which are dependent on position and/or alloy composition. These observations can be explained in terms of strain relaxation in a thin‐film specimen and deviations of the substrate from a perfect (100) orientation. The results have implications not only for the use of cross‐sectioned specimens in the characterization of strained‐layer heterostructures, but also for the band engineering of Si/GexSi1−xstrained‐layer superlattices and other materials which are grown on vicinal (100) and other low‐symmetry substrate orientations. In particular relaxed tetragonal and monoclinic structures may be quite relevant to the emerging science of strain‐induced lateral confinement of carriers in quantum well semiconductors.

ISSN:0003-6951    

DOI:10.1063/1.101015

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Laser‐induced anisotropic chemical etching of silicon is reported, by using a 488 nm Ar+laser in direct write mode and high‐pressure Cl2process gas. Surface modifications directly comparable with conventional anisotropic wet etching methods have been obtained. A main role in the process is played by the masking effect due to a thin uniform SiO2film grown on the Si substrate. An explanation of the etching mechanism is attempted.

ISSN:0003-6951    

DOI:10.1063/1.101443

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The reaction of Ti with pure Ge and several Ge‐Si alloys has been investigated with the double aim of understanding the reaction with Ge and of throwing some light on the still vexing problem of the Ti‐Si reaction. With pure Ge one observes first of all the formation of Ti6Ge5until complete consumption of the Ti is present. This is followed by the clearly identifiable nucleation of TiGe2, initially forming islands that grow laterally. With a 50‐50 (at. %) alloy of Si and Ge, one still observes distinct growth steps, but there is overlap between the growth of the initial phase, and the nucleation and growth of Ti(Ge,Si)2.

ISSN:0003-6951    

DOI:10.1063/1.101444

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Oxidation state selected titanium oxide thin films (TinO2n−1;n=1–∞) were deposited by a combination of a pulsed molecular beam source and an electron beam metal source. The oxidation state of titanium was controlled solely by the number of gas pulses and the temperature of a substrate. The conditions for depositing crystalline TinO2n−1thin films were determined.

ISSN:0003-6951    

DOI:10.1063/1.101445

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We describe the growth, ion beam, and photoluminescence characterization of Ga1−xInxAs/GaAs strained‐layer superlattices grown along the [111] axis. The layer thicknesses and composition are determined by Rutherford backscattering. Normal incidence channeling gives a minimum channeling yield of 5.7%. Strain conditions are found by off‐normal incidence channeling using the angular scan method. Comparison of the photoluminescence spectrum of the superlattice with theoretical calculations provides strong evidence for the existence of strain‐generated electric fields in [111] growth axis strained‐layer superlattices.

ISSN:0003-6951    

DOI:10.1063/1.101016

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Specular single‐crystal InP epilayers have been grown directly on Si(100) substrates by low‐pressure organometallic vapor phase epitaxy. The effects of the initial nucleation process on the structure properties of the films were investigated, and improvements in the growth technique leading to higher quality InP films are reported. The InP/Si epilayer grown under optimum conditions exhibits high optical quality compared with that of the InP homoepilayer. Post‐growth thermal annealing at 780 °C was also confirmed to be effective in improving the overall quality of InP‐on‐Si. The results presented are superior to those reported previously for InP/Si heteroepitaxy.

ISSN:0003-6951    

DOI:10.1063/1.101017

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

High quality ZnTe‐ZnSe strained‐layer superlattices grown on GaAs (001) substrates have been obtained by the hot wall epitaxy technique through introducing ZnTe and ZnSe buffers. Raman scattering from folded longitudinal acoustic phonons was observed. High‐angle satellite reflection peaks due to Cu K&agr;1 andK&agr;2 radiations were clearly resolved in the x‐ray diffraction patterns, and these patterns can be almost interpreted by a simple step model. The effect of the buffer layer on the strain of the superlattice is evaluated from the results of Raman scattering and x‐ray diffraction measurements.

ISSN:0003-6951    

DOI:10.1063/1.101000

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Single crystalline 3C‐SiC films were grown on a Si substrate by molecular beam epitaxy (MBE) using SiHCl3and C2H4gases. The optimal growth conditions were achieved at a growth temperature (Tsub) of 1000 °C and a gas pressure ratio (PSiHCl3/PC2H4) of 1/3 atPSiHCl3=1×10−5Torr. Prior to the essential growth of SiC, a carbonization process was performed with C2H4gas only. A continuous observation by reflection high‐energy electron diffraction (RHEED) was performed throughout the process of crystal growth. A series of RHEED patterns revealed that carbonization film could be grown at 750 °C and the lattice mismatch between Si and SiC crystals was satisfactorily relaxed. All processes of crystal growth were performed at a relatively low temperature.

ISSN:0003-6951    

DOI:10.1063/1.101001

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Heteroepitaxial Si/CoSi2/Si structures have been synthesized by high‐dose implantation of Co into (100) and (111) Si at an energy of 170 keV and subsequent annealing. In the as‐implanted state the implanted Co is found to be present as CoSi2. For a dose of 2×1017Co/cm2, the Co is present in the form of epitaxial precipitates, which exhibit both the aligned (A‐type) CoSi2and twinned (B‐type) orientation. For a higher dose of 3×1017Co/cm2, a monocrystalline epitaxial CoSi2layer near the top of the implanted Co distribution is formed during the implantation. The heteroepitaxial structures that are formed in this way are fully aligned. In contrast, when these structures are formed by sequential surface deposition techniques, twinning occurs at every Si/CoSi2interface. The formation of the aligned orientation of the buried CoSi2layer can be attributed to the larger stability of aligned precipitates as compared to twin‐oriented precipitates.

ISSN:0003-6951    

DOI:10.1063/1.101446

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The spectral characteristics of intraband absorption on bound‐free transitions in semiconductor quantum wells are analyzed. Numerical results indicate that both comparatively narrowband (∼30 meV) and broadband (≳200 meV) absorption may occur, which may be important in infrared detector design.

ISSN:0003-6951    

DOI:10.1063/1.100979

出版商:AIP    

年代:1989

数据来源: AIP