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The Aspect Ratio Trapping technique has been extensively evaluated for improving the quality of III-V heteroepitaxial films grown on Si, due to the potential for terminating defects at the sidewalls of SiO2 patterned trenches that enclose the growth region. However, defects propagating along the trench direction cannot be effectively confined with this technique. We studied the effect of the trench bottom geometry on the density of defects of GaAs fins, grown by metal-organic chemical vapor deposition on 300 mm Si (001) wafers inside narrow (<90 nm wide) trenches. Plan view and cross sectional Scanning Electron Microscopy and Transmission Electron Microscopy, together with High Resolution X-Ray Diffraction, were used to evaluate the crystal quality of GaAs. The prevalent defects that reach the top surface of GaAs fins are {111} twin planes propagating along the trench direction. The lowest density of twin planes, ∼8 × 108 cm−2, was achieved on “V” shaped bottom trenches, where GaAs nucleation occurs only on {111} Si planes, minimizing the interfacial energy and preventing the formation of antiphase boundaries.

Photon counting detectors are used in many diverse applications and are well-suited to situations in which a weak signal is present in a relatively benign background. Examples of successful system applications of photon-counting detectors include ladar, bio-aerosol detection, communication, and low-light imaging. A variety of practical photon-counting detectors have been developed employing materials and technologies that cover the waveband from deep ultraviolet (UV) to the near-infrared. However, until recently, photoemissive detectors (photomultiplier tubes (PMTs) and their variants) were the only viable technology for photon-counting in the deep UV region of the spectrum. While PMTs exhibit extremely low dark count rates and large active area, they have other characteristics which make them unsuitable for certain applications. The characteristics and performance limitations of PMTs that prevent their use in some applications include bandwidth limitations, high bias voltages, sensitivity to magnetic fields, low quantum efficiency, large volume and high cost.Recently, DARPA has initiated a program called Deep UV Avalanche Photodiode (DUVAP) to develop semiconductor alternatives to PMTs for use in the deep UV. The higher quantum efficiency of Geiger-mode avalanche photodiode (GM-APD) detectors and the ability to fabricate arrays of individually-addressable detectors will open up new applications in the deep UV. In this paper, we discuss the system design trades that must be considered in order to successfully replace low-dark count, large-area PMTs with high-dark count, small-area GM-APD detectors. We also discuss applications that will be enabled by the successful development of deep UV GM-APD arrays, and we present preliminary performance data for recently fabricated silicon carbide GM-APD arrays.

In the version of this Article originally published, the measured temperature difference ΔT was at the detector plane, whereas the definition of noise-equivalent temperature difference (NETD) in equation (2) requires ΔT to be a thermal scene temperature difference. Thus, the NETD terminology in equation (2) has now been replaced with temperature sensitivity (TS). This error has been corrected in the HTML and PDF versions of the Article. CORRIGENDUM

ABSTRACT:We report on the monolithic integration of GaSb and InAs fins on on-axis 300 mm Si (001) by metal-organic chemical vapor deposition. The thickness of the GaAs/Si (001) fins used as a template is optimized to allow the formation of {111} facets and the confinement of defects generated at the GaAs/GaSb and GaAs/InAs interfaces by means of the aspect ratio trapping technique. Anti-phase domains are avoided via a careful design of the GaAs/Si interface.Threading dislocations in GaSb are controlled through the formation of an interfacial misfit dislocation array along the GaSb/GaAs and interfaces. Defects on InAs are controlled through the promotion of a 2-dimensional growth, which spontaneously occurs on GaAs {111} planes. Results represent a step forward towards the integration of III-V nanoscale photonic and electronic components on a Si complementary metal-oxide-semiconductor compatible platform using a precisely engineered GaAs on Si template.2