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  • Structural and optical characterization of GaSb on Si (001) grown by Molecular Beam Epitaxy

    2019-04-17

    GaSb epilayers were grown on Si (001) using molecular beam epitaxy via AlSb quantum dots as an interfacial misfit (IMF) array between the Si substrates and GaSb epilayers. The effect of IMF array thickness, growth temperature and post annealing on the surface morphology, structural and optical properties of the GaSb on Si were investigated. Among five different IMF array thicknesses (5, 10, 20, 40 and 80 ML) that were used in this study, the best result was obtained from the sample with a 20 ML AlSb IMF array. Additionally, it was found that although the full width at half maximum (FWHM) and threading dislocation (TD) densities obtained from high resolution x-ray diffraction curves can be improved by increasing the growth temperature, a decrease in the photoluminescence (PL) signal and an increase in the surface roughness (RMS) emerged. On the other hand, the results indicate that by applying post annealing the GaSb epilayer crystal quality can be improved in terms of FWHM, TD density, PL signal or RMS depending on the post annealing temperature. By applying post annealing at 570 °C for 30 min we achieve a FWHM value of 260 arcsec for a 1 μm thick GaSb epilayer on Si (001) and improve the PL signal intensity without worsening the RMS value. Source:IOPscience For more information, please visit our website: www.semiconductorwafers.net, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com

  • In 2018, China's semiconductor materials market is 8.5 billion US dollars

    2019-04-08

    As an important part of new materials, semiconductor materials are the top priority of all countries in the world for the development of electronic information industry. It supports the development of localization of electronic information industry and is of great significance to industrial structure upgrading, national economy and national defense construction. In 2018, domestic semiconductor materials, with the joint efforts of all parties, achieved gratifying results in some areas, but the progress in the localization of key materials in the middle and high-end areas was slow, and the breakthroughs were few. The overall situation is not optimistic. China's semiconductor material segmentation progress is not uniform According to WSTS, in 2018, under the guidance of the memory market, the global semiconductor market continued to maintain rapid growth. The annual market size is expected to reach 477.94 billion US dollars, an increase of 15.9%. However, as the problem of the shortage of memory is alleviated, the growth rate of the global semiconductor market will be greatly reduced in 2019, and it is expected to increase by only 2.6% for the whole year. Domestically, the domestic semiconductor industry has a good business climate in the first half of 2018. Since the second half of the year, the domestic semiconductor industry has become increasingly weak due to the interfering factors of global consumer market demand and other factors. According to preliminary statistics, in 2018, China's semiconductor industry sales were 920.2 billion yuan, up 16.7% year-on-year in 2017. The uncertainties affecting the global economy in 2019 are still increasing. It is expected that the annual growth rate of semiconductor industry sales in China will fall to 14.8%. Semiconductor materials mainly include wafer manufacturing materials and packaging test materials. Among them, wafer manufacturing materials include silicon wafers, photoresists, photomasks, electronic special gases, wet chemicals, sputtering targets, CMP polishing materials, etc. In 2018, the overall market size of domestic wafer fabrication materials is about 2.82 billion. US dollar; packaging materials include lead frames, substrates, ceramic packaging materials, bonding wires, packaging resins, chip placement materials, etc. In 2018, the domestic packaging materials market size is about 5.68 billion US dollars. In 2018, the total market size of wafer fabrication materials and packaging test materials was approximately $8.5 billion. In 2018, the development of various segments of semiconductor materials in China is different. In terms of silicon wafers, the domestic construction boom has continued to emerge. As of the end of 2018, according to the capacity disclosed by each company's mass production line, the 8-inch wafer production capacity has reached 1.39 million pieces / month, and the capacity under construction has reached 2.7 million pieces / month. The production capacity of 12-inch wafers i...

  • Tuning the polarity of charge transport in InSb nanowires via heat treatment

    2019-04-02

    InSb nanowire (NW) arrays were prepared by pulsed electrodeposition combined with a porous template technique. The resulting polycrystalline material has a stoichiometric composition (In:Sb = 1:1) and a high length-to-diameter ratio. Based on a combination of Fourier transform infrared spectroscopy (FTIR) analysis and field-effect measurements, the band gap, the charge carrier polarity, the carrier concentration, the mobility and the effective mass for the InSb NWs was investigated. In this preliminary work, a transition from p-type to n-type charge transport was observed when the InSb NWs were subjected to annealing. Source:IOPscience For more information, please visit our website: www.semiconductorwafers.net, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com

  • Advantages, challenges and countermeasures of GaN application in RF field

    2019-03-25

    At present, gallium nitride (GaN) technology is no longer limited to power applications, and its advantages are also infiltrating into all corners of the RF/microwave industry, and the impact on the RF/microwave industry is growing, and should not be underestimated, because it can be used from space, military radar to cellular communications applications. Although GaN is often highly correlated with power amplifiers (PA), it has other use cases. Since its launch, the development of GaN has been remarkable, and with the advent of the 5G era, it may be more interesting. The role of GaN in radar and space Two variants of GaN technology are GaN-on-silicon (GaN-on-Si) and GaN-on-silicon-carbide(GaN-on-SiC). According to Damian McCann, director of engineering at Microsemi's RF/Microwave Discrete Products Division, GaN-on-SiC has contributed a great deal to space and military radar applications. Today, RF engineers are looking for new applications and solutions to take advantage of GaN-on-SiC. The ever-increasing levels of power and efficiency performance achieved by devices, especially in space and military radar applications. GaN is a wide bandgap semiconductor material with high hardness, mechanical stability, heat capacity, very low sensitivity to thermal radiation and thermal conductivity, and a better design for better size, weight and power (SWaP) Advantages. We also see GaN-on-SiC surpassing many competing technologies, even at lower frequencies. System designers will benefit from GaN-on-SiC technology. PAM-XIAMEN Doctor Victor explained that thermally coupled and highly integrated laminate technology, in combination with GaN-on-SiC, allows system designers to seek a higher level of integration, especially to extend the main radar to cover more of the same physical area. In the band, the second-order radar function is added. In space applications, the feasibility of GaN-on-SiC has recently been increasing, especially in applications where the efficiency of GaN is complementary to the ability to operate at higher frequencies. The power density of millimeter wave (mmWave) GaN brings a new set of design techniques that can be used to find higher levels of compensation. The solution must go beyond power and linearity in power compensation, and also need power control. Or run to a variable VSWR level. He also pointed out that GaN-on-SiC technology can replace the old klystron technology. The popularity of active electronically scanned arrays (AESAs) and phased array components in military and commercial space applications is also expected to reach new levels of power, even for GaN-on-SiC based monolithic microwave integrated circuits (MMICs), he said. In some cases replace the aging klystron technology. However, the limited number of qualified 0.15 micron GaN-on-SiC wafer foundries is a scarce resource on the market and needs further investment. GaN and 5G communication GaN technology is not limited to space and radar applications. It is driving inno...

  • The generation of crystal defects in Ge-on-insulator (GOI) layers in the Ge-condensation process

    2019-03-18

    The formation process of crystal defects in a Ge-on-insulator layer(GOI layer)  fabricated by oxidizing a SiGe-on-insulator (SGOI) layer, known as the Ge-condensation technique, is studied systematically. It is found that the crystal defects in the GOI layer are threading dislocations and microtwins that are formed mainly in the Ge fraction range larger than ~0.5. Also, when the Ge fraction reaches ~1 and the GOI layer is formed, the density of microtwins significantly decreases and their width considerably increases. The relaxation of compressive strain, observed in SGOI and GOI layers, is not attributable to the formation of the microtwins, but to the perfect dislocations that cannot be detected as defects in the lattice image. Source:IOPscience For more information, please visit our website: www.semiconductorwafers.net, send us email at sales@powerwaywafer.com and powerwaymaterial@gmail.com

  • Infrared spectroscopy characterization of 3C–SiC epitaxial layers on silicon

    2019-03-12

    We have measured the transmission Fourier transform infrared spectra of cubic silicon carbide (3C–SiC polytype) epitaxial layer with a 20 µm thickness on a 200 µm thick silicon substrate. Spectra were recorded in the 400–4000 cm−1 wavenumber range. A novel approach of IR spectra computations based on the recursion capability of the C programming language is presented on the basis of polarized light propagation in layered media using generalized Fresnel's equations. The complex refractive indices are the only input parameters. A remarkable agreement is found between all of the experimental SiC and Si spectral features and the calculated spectra. A comprehensive assignment of (i) the two fundamental transverse optical (TO) (790 cm−1) and longitudinal optical (LO) (970 cm−1) phonon modes of 3C–SiC, (ii) with their overtones (1522–1627 cm−1) and (iii) the two-phonon optical-acoustical summation bands (1311–1409 cm−1) is achieved on the basis of available literature data. This approach allows sorting out the respective contributions of the Si substrate and SiC upper layer. Such calculations can be applied to any medium, provided that the complex refractive index data are known. Source:IOPscience For more information, please visit our website: www.semiconductorwafers.net, send us email at sales@powerwaywafer.com and powerwaymaterial@gmail.com

  • Chemical mechanical polishing and nanomechanics of semiconductor CdZnTe single crystals

    2019-03-05

    (1 1 1), (1 1 0) Cd0.96Zn0.04Te and (1 1 1) Cd0.9Zn0.1Te semiconductor wafers grown by the modified vertical Bridgman method with dimensions of 10 mm × 10 mm × 2.5 mm were lapped with a 2–5 µm polygonal Al2O3 powder solution, and then chemically mechanically polished by an acid solution having nanoparticles with a diameter of around 5 nm, corresponding to the surface roughnesses Ra of 2.135 nm, 1.968 nm and 1.856 nm. The hardness and elastic modulus of (1 1 1), (1 1 0) Cd0.96Zn0.04Te and (1 1 1) Cd0.9Zn0.1Te single crystals are 1.21 GPa, 42.5 GPa; 1.02 GPa, 44.0 GPa; and 1.19 GPa, 43.4 GPa, respectively. After nanocutting is performed by the Berkovich nanoindenter, the surface roughness Ra of the (1 1 1) Cd0.9Zn0.1Te single crystal attains a 0.215 nm ultra-smooth surface. The hardness and elastic modulus of three kinds of CdZnTe single crystals decrease with the increase of indentation load. When the nanoindenter departs the surface of the crystals, the adherence effects are obvious for the three kinds of single crystals. This is attributed to the plastic sticking behavior of CdZnTe material at a nanoscale level. When the indentation load of the three kinds of CdZnTe single crystals is in the range of 4000–12 000 µN, the adhered CdZnTe material on the nanoindenter falls onto the surface and accumulates around the nanoindentation. Source:IOPscience For more information, please visit our website: www.semiconductorwafers.net, send us email at sales@powerwaywafer.com and powerwaymaterial@gmail.com

  • Study on AlGaN/GaN growth on carbonized Si substrate

    2019-02-26

    AlGaN/GaN films were grown on carbonized Si(111) substrates, which were employed to prevent impurities such as residual Ga atoms from reacting and deteriorating the surface of Si substrates. The cleaning process for the flow channel in metal organic chemical vapor deposition (MOCVD) could effectively be eliminated by using this carbonized Si substrate, and high-quality AlGaN/GaN films were obtained. Source:IOPscience For more information, please visit our website: www.semiconductorwafers.net, send us email at angel.ye@powerwaywafer.com or powerwaymaterial@gmail.com

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