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  • Mid-infrared InAs/GaSb strained layer superlattice detectors with nBn design grown on a GaAs substrate

    2019-09-29

    We report on a type-II InAs/GaSb strained layer superlattice (SLS) photodetector (λ_{\rm cut\hbox{-}off}  ~4.3 µm at 77 K) with nBn design grown on a GaAs substrate using interfacial misfit dislocation arrays to minimize threading dislocations in the active region. At 77 K and 0.1 V of the applied bias, the dark current density was equal to 6 × 10−4 A cm−2 and the maximum specific detectivity D* was estimated to 1.2 × 1011 Jones (at 0 V). At 293 K, the zero-bias D* was found to be ~109 Jones which is comparable to the nBn InAs/GaSb SLS detector grown on the GaSb substrate. Source:IOPscience For more information, please visit our website: www.semiconductorwafers.net, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com

  • Overview of recent direct wafer bonding advances and applications

    2019-09-18

    Direct wafer bonding processes are being increasingly used to achieve innovative stacking structures. Many of them have already been implemented in industrial applications. This article looks at direct bonding mechanisms, processes developed recently and trends. Homogeneous and heterogeneous bonded structures have been successfully achieved with various materials. Active, insulating or conductive materials have been widely investigated. This article gives an overview of Si and SiO2 direct wafer bonding processes and mechanisms, silicon-on-insulator type bonding, diverse material stacking and the transfer of devices. Direct bonding clearly enables the emergence and development of new applications, such as for microelectronics, microtechnologies, sensors, MEMs, optical devices, biotechnologies and 3D integration. Source:IOPscience For more information, please visit our website: www.semiconductorwafers.net, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com

  • Japanese Journal of Applied Physics logo A Novel Diffusion Resistant P-Base Region Implantation for Accumulation Mode 4H–SiC Epi-Channel Field Effect Transistor

    2019-09-11

    A novel implantation technique using the carbon (C) and boron (B) sequential implantation is employed to control the B lateral and vertical diffusion from the p-base region of the planar silicon carbide (SiC) epi-channel field effect transistor (ECFET). The current deep level transient spectroscopy measurements were performed to establish the inter-correlation between the B enhanced diffusion and the electrically active defects introduced by the C and B sequential implantation. It was found that the formation of deep defect level is completely suppressed for the same ratio (C:B=10:1) as that for the B diffusion in 4H–SiC. A diffusion mechanism which is correlated to the formation of D center was proposed to account for the experimentally observed B enhanced diffusion. The effectiveness of C and B implantation technique in suppressing the junction field effect transistor (JFET) pinch effect is clearly visible from the 3–4 fold increase in drain current of fabricated 4H–SiC ECFET for p-base spacing which was scaled down to about 3 µm. This novel diffusion resistant implantation technique open doors for the larger packing densities through unit-cell pitch reduction for SiC high power device applications. Source:IOPscience For more information, please visit our website: www.semiconductorwafers.net, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com

  • Adding a Bit of Artificiality Makes Graphene Real for Electronics

    2019-08-28

     We believes that one of the electronic capabilities for this device could be selecting the strength of the spin-orbit coupling in a p-type GaAs quantum well. This could lead to the creation of a topological insulator, which is an insulator on the inside but a conductor on the outside. Such an insulator could in turn enable so-called topological quantum computation, which is a theoretical approach to quantum computing that could be far more robust than current methods. This capability does not exist in natural graphene or other artificial graphene systems. Source:.ieee For more information, please visit our website: www.semiconductorwafers.net, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com

  • Two inch GaN substrates fabricated by the near equilibrium ammonothermal (NEAT) method

    2019-08-19

    This paper reports two inch gallium nitride (GaN) substrates fabricated from bulk GaN crystals grown in the near equilibrium ammonothermal method. 2'' GaN wafers sliced from bulk GaN crystals have a full width half maximum of the 002 X-ray rocking curve of 50 arcsec or less, a dislocation density of mid-105 cm−2 or less, and an electron density of about 2 × 1019 cm−3. The high electron density is attributed to an oxygen impurity in the crystal. Through extensive surface preparation, the Ga surface of the wafer shows an atomic step structure. Additionally, removal of subsurface damage was confirmed with grazing angle X-ray rocking curve measurements from the 114 diffraction. High-power p–n diode structures were grown with metalorganic chemical vapor deposition. The fabricated devices showed a breakdown voltage of over 1200 V with sufficiently low series resistance. Source:IOPscience For more information, please visit our website: www.semiconductorwafers.net, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com

  • Enhancement of the quality of InAsSb epilayers using InAsSb graded and InSb buffer layers grown by hot wall epitaxy

    2019-08-12

    We have investigated the structural and electrical properties of InAsxSb1−x epilayers grown on GaAs(0 0 1) substrates by hot wall epitaxy. The epilayers were grown on an InAsSb graded layer and an InSb buffer layer. The arsenic composition (x) of the InAsxSb1−x epilayer was calculated using x-ray diffraction and found to be 0.5. The graded layers were grown with As temperature gradients of 2 and 0.5 °C min−1. The three-dimensional (3D) island growth due to the large lattice mismatch between InAsSb and GaAs was observed by scanning electron microscopy. As the thicknesses of the InAsSb graded layer and the InSb buffer layer are increased, a transition from 3D island growth to two-dimensional plateau-like growth is observed. The x-ray rocking curve measurements indicate that full-width at half-maximum values of the epilayers were decreased by using the graded and buffer layers. A dramatic enhancement of the electron mobility of the grown layers was observed by Hall effect measurements. Source:IOPscience For more information, please visit our website: www.semiconductorwafers.net, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com

  • Quality Variation of ZnSe Heteroepitaxial Layers Correlated with Nonuniformity in the GaAs Substrate Wafer

    2019-08-06

    ZnSe layers are grown heteroepitaxially on substrates cut from a LEC-grown, undoped semi-insulating GaAs(100) wafer along the diameter parallel to the [001] axis. The intensities of free-exciton photoluminescence and X-ray diffraction from the ZnSe layers show an M-shaped profile along the GaAs wafer diameter, and are inversely correlated with the etch-pit-density distribution of the GaAs wafer. This observation gives, for the first time, experimental evidence that the quality of ZnSe heteroepitaxial layers grown by recent epitaxial techniques can be limited by the quality of GaAs substrates. Source:IOPscience For more information, please visit our website: www.semiconductorwafers.net, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com

  • Highly boron-doped germanium layers on Si(001) grown by carbon-mediated epitaxy

    2019-07-29

    Smooth and fully relaxed highly boron-doped germanium layers were grown directly on Si(001) substrates using carbon-mediated epitaxy. A doping level of  was measured by several methods. Using high-resolution x-ray diffraction we observed different lattice parameters for intrinsic and highly boron-doped samples. A lattice parameter of a Ge:B = 5.653 Å was calculated using the results obtained by reciprocal space mapping around the (113) reflection and the model of tetragonal distortion. The observed lattice contraction was adapted and brought in accordance with a theoretical model developed for ultra-highly boron-doped silicon. Raman spectroscopy was performed on the intrinsic and doped samples. A shift in the first order phonon scattering peak was observed and attributed to the high doping level. A doping level of  was calculated by comparison with literature. We also observed a difference between the intrinsic and doped sample in the range of second order phonon scattering. Here, an intense peak is visible at  for the doped samples. This peak was attributed to the bond between germanium and the boron isotope 11B. Source:IOPscience For more information, please visit our website: www.semiconductorwafers.net, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com

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