Nanotopography is a part of the overall silicon wafer surface topography and may affect yield in present chip manufacturing processes (like CMP). Techniques combining laser triangulation and high precision scanning stages are now capable to detect flatness deviations in the nanometer range on the entire wafer surface. In addition spectral analysis of the raw height data (e.g., power spectral density calculation) is applied to quantify the nanotopography of state of the art polished wafers over a wide range of the spatial wavelengths. Keywords:Waviness,Surface inspection,Surface roughness,Geometry measurements,PSD, Source:ScienceDirect For more information, please visit our website: http://www.semiconductorwafers.net, send us email at angel.ye@powerwaywafer.com or powerwaymaterial@gmail.com.
Xiamen Powerway Advanced Material Co.,Ltd., a leading supplier of InAlAs and other related products and services announced the new availability of size 2” is on mass production in 2017. This new product represents a natural addition to PAM-XIAMEN’s product line. Dr. Shaka, said, “We are pleased to offer InAlAs layer to our customers including many who are developing better and more reliable for broadband quantum cascade lasers. Our InAlAs layer has excellent properties, Aluminium indium arsenide is used e.g. as a buffer layer in metamorphic HEMT transistors, where it serves to adjust the lattice constant differences between the GaAs substrate and the GaInAs channel. It can be also used to form alternate layers with indium gallium arsenide, which act as quantum wells; these structures are used in e.g. broadband quantum cascade lasers. The availability improve boule growth and wafering processes.” and “Our customers can now benefit from the increased device yield expected when developing advanced transistors on a square substrate. Our InAlAs layer are natural by products of our ongoing efforts, currently we are devoted to continuously develop more reliable products.” PAM-XIAMEN’s improved InAlAs product line has benefited from strong tech. support from Native University and Laboratory Center. Now it shows an example as follows: n++InGaAs (~30nm) (5X10^19cm^-3, InP (undoped) (~3~5nm), In0.7Ga0.3As (undoped) (3nm), InAs (undoped) (2nm) In0.53Ga0.47As (undoped) (5nm), In0.52Al0.48As (undoped) (~15nm), InP (~5nm), SiO2(~100nm), Si (wafer). About Xiamen Powerway Advanced Material Co., Ltd Found in 1990, Xiamen Powerway Advanced Material Co., Ltd (PAM-XIAMEN) is a leading manufacturer of compound semiconductor material in China. PAM-XIAMEN develops advanced crystal growth and epitaxy technologies, manufacturing processes, engineered substrates and semiconductor devices. PAM-XIAMEN’s technologies enable higher performance and lower cost manufacturing of semiconductor wafer. About InAlAs Aluminium indium arsenide, also indium aluminium arsenide or AlInAs (AlxIn1−xAs), is a semiconductor material with very nearly the same lattice constant as GaInAs, but a largerbandgap. The x in the formula above is a number between 0 and 1 – this indicates an arbitrary alloy between InAs and AlAs.The formula AlInAs should be considered an abbreviated form of the above, rather than any particular ratio.Aluminium indium arsenide is used e.g. as a buffer layer in metamorphic HEMT transistors, where it serves to adjust the lattice constant differences between the GaAs substrate and the GaInAs channel. It can be also used to form alternate layers with indium gallium arsenide, which act as quantum wells; these structures are used in e.g. broadband quantum cascade lasers. Q&A Q: How about the III-V on Si? I am still interested.Can you introduce the buffer layer between Si substrate and III-V active layers? A: Silicon epitaxial nucleation needs, usually the first l...
A Lawrence Livermore National Laboratory team lead by Anna Hiszpanski has devised guidelines for an alternative to anti-reflective coatings on optical devices such as solar cells, glasses and cameras, by engineering their surfaces with layers of hierarchical micro- and nanometer length structures. Credit: Lawrence Livermore National Laboratory When it comes to solar cells, less is more—the less their surfaces reflect a sun’s rays, the more energy can be generated. A typical fix to the problem of reflectivity is an anti-reflective coating, but that might not always be the best solution, depending on the application. Lawrence Livermore National Laboratory (LLNL) researchers have come up with guidelines for an alternative to anti-reflective coatings on optical devices such as solar cells, glasses and cameras, finding that reflectivity of silicon optics can be reduced to as little as 1 percent by engineering their surfaces with layers of hierarchical micro- and nanometer length structures. A team of LLNL researchers, led by chemical engineer Anna Hiszpanski and UC Santa Cruz graduate student Juan Diaz Leon, described the parameters in a recent paper published by the journal Advanced Optical Materials . The technology has its roots in nature, mimicking the hierarchical structures found in the eye of a moth, allowing them to absorb more light and better navigate in darkness. “It’s a different anti-reflective approach,” said Hiszpanski, who performed the experiments and was the co-lead author on the paper. “The design rules for these hierarchical anti-reflective structures haven’t been explicitly laid out in these size scales. I’m hopeful they will enable others to more quickly design and fabricate optimal structures with the anti-reflective properties needed by their applications.” Reflections from surfaces can be a major challenge in optics, according to Diaz Leon, who performed the computer simulations. Typically, single-layer anti-reflection coatings are used to counter it, using destructive interference to eliminate reflections for only a narrow band of wavelengths and viewing angles. However, when reduced reflectivity across multiple wavelengths and viewing angles is desired, different approaches are needed, he said. In the study, the group found the average hemispherical or total reflectance of silicon can be as much as 38 percent, but if only micro-scale pyramidal structures are engineered into silicon, as is common in solar cells, reflectance drops to about 11 percent. However, by stacking micro- and nano-sized arrays on top of the larger structures, total reflectivity can be reduced to as little as between 1 percent and 2 percent regardless of the angle of incoming light. If solar cells could be textured to collect more light at all angles, Hiszpanski said, they wouldn’t have to be tracked with the sun’s position in the sky and could potentially be more efficient at converting energy. When used in eyeglasses, hierarchical structures could elim...
Xiamen Powerway Advanced Material Co.,Ltd., a leading supplier of AlGaN and other related products and services announced the new availability of size 2” is on mass production in 2017. This new product represents a natural addition to PAM-XIAMEN’s product line. Dr. Shaka, said, “We are pleased to offer AlGaN material to our customers including many who are developing better and more reliable for light-emitting diodes operating in blue to ultraviolet region. Our AlGaN material has excellent properties, the bandgap of AlxGa1−xN can be tailored from 3.4eV (xAl=0) to 6.2eV (xAl=1). It is also used in blue semiconductor lasers and in detectors of ultraviolet radiation, and in AlGaN/GaN High-electron-mobility transistors. The availability improve boule growth and wafering processes.” and “Our customers can now benefit from the increased device yield expected when developing advanced transistors on a square substrate. Our AlGaN material are natural by products of our ongoing efforts, currently we are devoted to continuously develop more reliable products.” PAM-XIAMEN’s improved AlGaN product line has benefited from strong tech,support from Native University and Laboratory Center. Now it shows an example as follows: 0) Substrate: H-R Si (111) 1) Buffer: AlGaN – 1,5 µm 2) Channel: GaN – 150 nm 3) Barrier: AlN – 6 nm 4) In-situ SiN -3 nm 5) PECVD SiN – 50 nm About Xiamen Powerway Advanced Material Co., Ltd Found in 1990, Xiamen Powerway Advanced Material Co., Ltd (PAM-XIAMEN) is a leading manufacturer of compound semiconductor material in China. PAM-XIAMEN develops advanced crystal growth and epitaxy technologies, manufacturing processes, engineered substrates and semiconductor devices. PAM-XIAMEN’s technologies enable higher performance and lower cost manufacturing of semiconductor wafer. About AlGaN Aluminium gallium nitride (AlGaN) is a semiconductor material. It is any alloy of aluminium nitride and gallium nitride. The bandgap of AlxGa1−xN can be tailored from 3.4eV (xAl=0) to 6.2eV (xAl=1).[1] AlGaN is used to manufacture light-emitting diodes operating in blue to ultraviolet region, where wavelengths down to 250 nm (far UV) were achieved. It is also used in blue semiconductor lasers. It is also used in detectors of ultraviolet radiation, and in AlGaN/GaN High-electron-mobility transistors. AlGaN is often used together with gallium nitride or aluminium nitride, forming heterojunctions.AlGaN layers can be also grown on sapphire. There are many areas of potential utilization of the alloy AlxGa1-xN, not the least of which are ultraviolet detector applications. These include flame and heat sensors,missile plume detection, and secure-from-earth inter-satellite communications. The AlxGa1-xN bandgap can be tailored from 4.3eV (xAl=0) to 6.2eV (xAl=1), corresponding to a band-edge wavelength range of 365nm to 200nm, to suit each unique application. Solar radiation below approximately 300nm wavelength is absorbed by ozone in the atmosphere. Thus, for ap...
Veeco Instruments completed a strategic initiative with ALLOS Semiconductors (ALLOS) to demonstrate 200mm GaN-on-Si wafers for Blue/Green microLED production. Veeco teamed up with ALLOS to transfer their proprietary epitaxy technology onto the Propel SingleWafer MOCVD System to enable micro-LED production on existing silicon production lines. (Image: Micro LED Adafruit Industries via Flickr CC2.0) “With the Propel reactor, we have an MOCVD technology that is capable of high yielding GaN Epitaxy that meets all the requirements for processing micro-LED devices in 200 millimeter silicon production lines,” said Burkhard Slischka, CEO of ALLOS Semiconductors. “Within one month we established our technology on Propel and have achieved crack-free, meltback-free wafers with less than 30 micrometers bow, high crystal quality, superior thickness uniformity and wavelength uniformity of less than one nanometer. Together with Veeco, ALLOS is looking forward to making this technology more widely available to the micro-LED ecosystem.” Micro-LED display technology consists of <30×30 square micron red, green, blue (RGB) inorganic LEDs that are transferred to the display backplane to form sub-pixels. Direct emission from these high efficiency LEDs offers lower power consumption compared with OLED and LCD while providing superior brightness and contrast for mobile displays, TV and wearables. The manufacturing of micro-LEDs requires high quality, uniform epitaxial wafers to meet the display yield and cost targets. “In contrast to competing MOCVD platforms, Propel offers leading-edge uniformity and simultaneously achieves excellent film quality as a result of the wide process window afforded by Veeco’s TurboDisc technology,” said Peo Hansson, Ph.D., Senior Vice President and General Manager of Veeco MOCVD Operations. “Combining Veeco’s leading MOCVD expertise with ALLOS’ GaN-on-Silicon epi-wafer technology enables our customers to develop micro-LEDs cost effectively for new applications in new markets.” Keywords:MOCVD,Veeco,Micro LED,Allos,GaN-on-Si wafer, Source:LEDinside For more information, please visit our website: http://www.semiconductorwafers.net, send us email at angel.ye@powerwaywafer.com or powerwaymaterial@gmail.com.
Xiamen Powerway Advanced Material Co.,Ltd., a leading supplier of GaN and other related products and services announced the new availability of size 2” is on mass production in 2017. This new product represents a natural addition to PAM-XIAMEN’s product line. Dr. Shaka, said, “We are pleased to offer GaN substrate to our customers including many who are developing better and more reliable for GaN HEMTs, which have found immediate use in various wireless infrastructure applications due to their high efficiency and high voltage operation. Second generation technology with shorter gate lengths will be addressing higher frequency telecom and aerospace applications. Our GaN substrate has excellent properties, it’s a very hard, mechanically stable wide bandgap semiconductor material with high heat capacity and thermal conductivity. In its pure form it resists cracking and can be deposited in thin film on sapphire or silicon carbide, despite the mismatch in their lattice constants. GaN can be doped with silicon (Si) or with oxygen to n-type and with magnesium (Mg) to p-type; however, the Si and Mg atoms change the way the GaN crystals grow, introducing tensile stresses and making them brittle. Gallium nitride compounds also tend to have a high dislocation density, on the order of a hundred million to ten billion defects per square centimeter. The availability improve boule growth and wafering processes.” and “Our customers can now benefit from the increased device yield expected when developing advanced transistors on a square substrate. Our GaN substrate are natural by products of our ongoing efforts, currently we are devoted to continuously develop more reliable products.” PAM-XIAMEN’s improved GaN product line has benefited from strong tech,support from Native University and Laboratory Center. Now it shows an example as follows: FS GaN substrate, n type, undoped: Resistivity<0.5 ohm.cm, carrier concentration: (1-5)E17 FS GaN substrate, n type, Si doped: Resistivity<0.5 ohm.cm, carrier concentration: (1-3)E18, About Xiamen Powerway Advanced Material Co., Ltd Found in 1990, Xiamen Powerway Advanced Material Co., Ltd (PAM-XIAMEN) is a leading manufacturer of compound semiconductor material in China. PAM-XIAMEN develops advanced crystal growth and epitaxy technologies, manufacturing processes, engineered substrates and semiconductor devices. PAM-XIAMEN’s technologies enable higher performance and lower cost manufacturing of semiconductor wafer. About GaN Gallium nitride (GaN) is a binary III/V direct bandgap semiconductor commonly used in light-emitting diodes since the 1990s. The compound is a very hard material that has a Wurtzite crystal structure. Its wide band gap of 3.4 eV affords it special properties for applications in optoelectronic, high-power and high-frequency devices. For example, GaN is the substrate which makes violet (405 nm) laser diodes possible, without use of nonlinear optical frequency-doubling. Its sensitivi...
A new material produced by Juejun Hu and his team can be repeatedly stretched without losing its optical properties. Credit: Massachusetts Institute of Technology Researchers at MIT and several other institutions have developed a method for making photonic devices—similar to electronic devices but based on light rather than electricity—that can bend and stretch without damage. The devices could find uses in cables to connect computing devices, or in diagnostic and monitoring systems that could be attached to the skin or implanted in the body, flexing easily with the natural tissue. The findings, which involve the use of a specialized kind of glass called chalcogenide, are described in two papers by MIT Associate Professor Juejun Hu and more than a dozen others at MIT, the University of Central Florida, and universities in China and France. The paper is slated for publication soon in Light: Science and Applications. Hu, who is the Merton C. Flemings Associate Professor of Materials Science and Engineering, says that many people are interested in the possibility of optical technologies that can stretch and bend, especially for applications such as skin-mounted monitoring devices that could directly sense optical signals. Such devices might, for example, simultaneously detect heart rate,blood oxygen levels, and even blood pressure. Photonics devices process light beams directly, using systems of LEDs, lenses, and mirrors fabricated with the same kinds of processes used to manufacture electronic microchips. Using light beams rather than a flow of electrons can have advantages for many applications; if the original data is light-based, for example, optical processing avoids the need for a conversion process. But most current photonics devices are fabricated from rigid materials on rigid substrates, Hu says, and thus have an “inherent mismatch” for applications that “should be soft like human skin.” But most soft materials, including most polymers, have a low refractive index, which leads to a poor ability to confine a light beam. Instead of using such flexible materials, Hu and his team took a novel approach: They formed the stiff material—in this case a thin layer of a type of glass called chalcogenide—into a spring-like coil. Just as steel can be made to stretch and bend when formed into a spring, the architecture of this glass coil allows it to stretch and bend freely while maintaining its desirable optical properties. A view of the lab setup that was used to test the new materials, demonstrating that they could be stretched and flexed without losing the ability to confine light beams and carry out photonic processing. Credit: Massachusetts Institute of Technology “You end up with something as flexible as rubber, that can bend and stretch, and still has a high refractive index and is very transparent,” Hu says. Tests have shown that such spring-like configurations, made directly on a polymer substrate, can undergo thousands of stretching cycles wit...
Abstract For solar cell application, the stability of interface passivation quality to in-field conditions is crucial. We have performed an experiment to test the resilience of different aluminium oxide based passivation schemes to illumination at 75 °C. Different thermal treatments to activate the passivation and/or simulate contact firing were performed before light soaking. The experiment was performed on 1 Ωcm float-zone silicon of both p- and n-type doping. The study demonstrates that good passivation quality can be achieved both by atomic layer deposition and by PECVD and that addition of silicon nitride capping layers greatly enhances thermal stability. On p-type wafers a severe but temporary degradation of the electrical quality of the wafer bulk was observed during the first hours upon application of such capping layers. Besides this effect, reasonable temporal stability of the effective lifetime was observed for p-type samples while n-type samples featured excellent long-term stability. Keywords:float zone silicon;aluminum oxide passivation;stability;light soaking 1. Introduction Recent improvements of the efficiency of industrially feasible solar cell concepts have been driven by improvements of the material bulk quality and reduction of recombination losses at the surfaces. This was supported by the emergence of passivation schemes based on aluminium oxide for industrial application due to their good passivation properties. The good passivation quality of aluminium oxide layers is well established in literature and demonstrated by a multitude of studies, e.g. [1] and references therein. Studies concerning the stability of passivation schemes usually focus on one system and/or one stress factor such as dark storage, illumination or damp heat testing conditions [2-4]. To generalize the previous findings we have performed a study comparing multiple different schemes at a stress factor combination that occurs upon photovoltaic module operation: illumination at elevated temperature. Nomenclature Al2O3 stoichiometric aluminium oxide layers deposited by P-ALD AlOx aluminium oxide layers deposited by PECVD FZ float-zone LeTID Light and elevated temperature induced degradation P-ALD plasma-activated atomic layer deposition PECVD plasma-enhanced chemical vapour deposition PLI photoluminescence imaging RTP rapid thermal processing SRV surface recombination velocity 2. Experiment 2.1. Sample preparation All experiments were performed on four inch float-zone (FZ) silicon wafers. After wet chemical cleaning, an oxidation treatment at 1050 °C was performed to stabilize the wafer bulk quality, as suggested by Grant et al. [5]. The resulting silicon oxide layer was subsequently etched off. To demonstrate whether the thermal treatment affected the experiment, a reference sample group was not subjected to it. The investigated aluminium oxide layers of 20 or 30 nm thickness were deposited on both wafer sides either by plasma-activated atomic layer deposi...
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