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In order to quantitatively analyze the contribution of each scattering factor toward the total carrier mobility, we use a new convenient figure-of-merit, named a percentage impact. The mobility limit due to a scattering factor, which is widely used to summarize a scattering analysis, has its own advantage. However, a mobility limit is not quite appropriate for the above purpose. A comprehensive understanding of the difference in contribution among many scattering factors toward the total carrier mobility can be obtained by evaluating percentage impacts of scattering factors, which can be straightforwardly calculated from their mobility limits and the total mobility. Our percentage impact analysis shows that threading dislocation is one of the dominant scattering factors for the electron transport in InSb quantum wells at room temperature. [ABSTRACT FROM AUTHOR]

The theoretical analysis of threading dislocation density reduction in growing porous GaN layers based on reaction-kinetics model is developed. The results obtained by parametric modeling are in agreement with available experimental data. [ABSTRACT FROM AUTHOR]

Research on GaN, AlN, InN (III-N) and their alloys is achieving new heights due their high potential applications in photonics and electronics. III-N semiconductors are mostly grown epitaxially on sapphire, and due to the large lattice mismatch and the differences in the thermal expansion coefficients, the structures usually contain many threading dislocations (TDs). While their structural properties have been widely investigated, their electrical characteristics and their role in the transport properties of the devices are still debated. In the present contribution we will show conductive AFM studies of TDs in GaN and Al/In GaN ternary alloys to evidence the role of strain, different surface polarity and composition on their electrical properties. Local I-V curves measured at TDs allowed us to clarify their role in the macroscopic electrical properties (leakage current, mobilities) of III-N based devices. Samples obtained by different growers (AIXTRON, III-V Lab) were studied. The comparison between the results obtained in the different alloys allowed us to understand the role of In and Al on the TDs electrical properties. [ABSTRACT FROM AUTHOR]

Epitaxial strained Si/Si1-xGex wafers with 14% to 41% Ge were used in this study. A two-step etching procedure was optimized to selectively delineate threading dislocations (TDs) exiting the top strained Si (sSi) layer. The first step is a short duration etch in a diluted Secco or Schimmel solution to enable a pipe to form preferentially at TDs on the top sSi layer, while allowing a thin sSi layer to remain as a cap on the underlying SiGe layer. After the TDs have been opened-up, the sample is further etched in HF(49%):H2O2(30%):HAc =1:2:3, which selectively etches the underlying SiGe in the vicinity of TD pipes, but essentially does not attack the Si cap. Thus, the TD etch pit contrast is enhanced and well resolved under an optical microscope. We have also applied low-temperature MOS-EBIC to electrically examine TDs under accumulation mode bias, which allows separation of MDs and TDs, and selective imaging of electrically active TDs up to the top oxidized sSi layer. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]