摘要:

We show that thin Al0.48In0.52As layers in Ga0.47In0.53As alloy films, can be used to trap free carriers, and produce high resistivity materials suitable for 1.55 &mgr;m photoconductive detectors. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114948

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Transmission electron microscopy has been used to characterize the microstructure of heteroepitaxial CdTe (111) layers grown by molecular beam epitaxy directly on nominal and misoriented Si(001) substrates. High‐resolution electron micrographs showing atomic‐scale details of the CdTe (111)/Si(001) interface have been recorded. Layer quality depended on the substrate tilt parameters, including the offcut orientation angle &thgr;, and the azimuthal angle &fgr; relative to [110]. Small &fgr; values (4° and 10°) gave high densities of stacking fault twins throughout the epilayer whereas larger misorientation angles led to a rapid falloff away from the substrate. Under optimized growth conditions, the occurrence of twins effectively dropped to zero within a distance of less than 2.5 &mgr;m from the substrate surface. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114949

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We demonstrate the heterodyne detection of two CO2laser signals offset in frequency up to 82.16 GHz using a multiple quantum well intersubband infrared photodetector. The high frequency is reached by down conversion using the detector itself as a microwave or millimeter‐wave mixer. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114950

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The reactions during annealing of a Co/Ti bilayer structure on Si(001) were studiedinsituto reveal the roles of the Ti interlayer and the annealing ambient on the formation of epitaxial CoSi2. We shown that an oxygen contaminant in the nitrogen annealing gas is needed to form a stable, Co–Ti–O (spinel) membrane at the metal/Si interface that limits diffusion and is crucial for the perfection of epitaxial CoSi2. Annealing in vacuum or otherwise inert environments led to polycrystalline CoSi2films and no spinel phase. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114951

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We have grown ∼10 nm O2and N2O‐oxides on Si(100) by RTO (rapid thermal oxidation) over the temperature range 800–1200 °C. Although the growth rates of both oxides exhibit Arrhenius behavior over the entire temperature range, the N2O‐oxides exhibit a large change in the Arrhenius preexponential factor for oxidation temperatures greater than 1000 °C. Above this temperature, N2O‐oxides grow a factor of 5 slower than O2oxides. Below this temperature, N2O‐oxide growth rates approach those of O2‐oxides. This growth rate inflection can be explained in terms of N incorporation, which increases with increasing oxidation temperature. The equivalent of one monolayer of N coverage is achieved at about 1000 °C, coincident with the inflection. The incorporated N retards the linear growth of the thin N2O‐oxides either by occupying oxidation reaction sites or inhibiting transport of oxidant species to the vicinity of the interface. ©1995 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.114952

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We have observed a significant persistent photoconductivity effect in narrow InGaAs/InP quantum wells grown by metalorganic vapor phase epitaxy. This effect enables a detailed study of transport parameters as a function of the electron density. In this way, the interface roughness scattering can be separated from the strongly density dependent Coulomb scattering. For different preparation conditions, we find a strong correlation between the amount of interface roughness scattering and structural data of the interface. The ratio of quantum to classical scattering times remains ≪1 even in the case when Coulomb scattering is not the predominant scattering mechanism. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114953

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The local temperature of aluminum metallization is measured directly during electromigration. High resolution thermography is used to detect void dynamics induced by a dc current. In the vicinity of the growing area, infrared radiation pulses less than 0.5 s wide are observed concomitant with resistance pulses. Their amplitudes are found to correspond to a temperature increase of more than 200 °C, which locally exceeds the melting point of aluminum metallization. These pulses occur as a consequence of void movement. Healing of voids is discussed along with the results. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114954

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Using image processing algorithms based on nonlinear imaging theory, we have analyzed high‐resolution transmission electron microscopy images of InAs/GaSb superlattices (SLs) grown by molecular beam epitaxy. Our analysis indicates that InSb‐like interfaces have a roughness of 1 monolayer (ML), for a SL grown on a GaSb buffer layer. For GaAs‐like interfaces, however, the interface roughness is found to be 2 MLs when the SL is grown on a GaSb buffer. For SLs grown on an InAs buffer, the roughness of GaAs‐like interfaces (3 MLs) is also greater than that of InSb‐like interfaces (2MLs). These results suggest two general observations. The first is that GaAs‐like interfaces are rougher than InSb‐like interfaces. This difference may be due to the high surface energy of GaAs as compared to InSb. The second observation is that interface roughness is greater for an InAs/GaSb SL grown on an InAs buffer layer than for the same SL grown on a GaSb buffer layer. This difference in interface roughness may be due to InAs SL layers being in tension when grown on a GaSb buffer layer, whereas GaSb SL layers are under compression when grown on an InAs buffer layer. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114955

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The influence of the process environment on thermally induced intermixing of GaAs/AlAs/AlGaAs double barrier quantum wells is investigated by effecting different low energy reactive ion etch (RIE) surface treatments and then depositing PECVD/sputtered cap layers prior to annealing. We observe photoluminescence blue shifts, small red shifts and total intermixing, dependent on the actual combination of cap material and RIE treatment. The results indicate that the RIE surface damage is an important factor for the onset of the intermixing process and that PECVD processes may require a few monolayers thick surface disordering in order to trigger off the quantum well intermixing, even using SiO2cap layers. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114956

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A simple model is proposed to analyze microwave properties of thin superconducting strips with degraded edge regions. A high resistance edge is assumed in the superconducting strip. It is shown that with increased temperature more current will flow inside the superconducting strip away from the damaged edge resulting in a reduction of effective surface resistance. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114957

出版商:AIP    

年代:1995

数据来源: AIP