The VCSEL structure offers several distinct advantages in manufacturing and performance that have made it a popular choice for fibre optics data communication. However, high performance multi-channel fiber optic transmitters pose special requirements for the laser and other components. Vertical integration within Avago Technologies enables the specialized design of the VCSEL, optics and IC laser driver to meet these requirements.
Strain techniques, such as incorporating SiGe, should boost performance in future generations of CMOS silicon transistors without the need to radically scale transistor dimensions. Although strain is already used for some technology nodes, more knowledge needs to be developed, e.g. on the relationship between strain, carrier mobility and device performance, to employ it further. Also, combination with other options, such as MuGFETs, high-k materials and metal gates, is being considered.
At present renewable energy sources consist mainly of hydro power and wind energy, with the latter becoming increasingly important. However, the number of solar cells being produced yearly (in terms of watts produced by these solar cells under a standardized spectrum) has been growing consistently over the last 10 years, with growth rates between 25 and 70%/year; for 2005 solar cell production reached 1.7GW. This terrestrial photovoltaic (PV) market is currently dominated by flat plate modules incorporating Si solar cells. However, to sustain the present growth rate of terrestrial PV, the use of expensive semiconductor material must be minimized, necessitating the development of new technologies.
The desire to “see” in complete darkness or through obscurants such as smoke or fog has driven the development and adoption of thermal imaging technology in numerous industries. Thermal imaging is the translation of a scene's heat signature-the Long Wavelength Infrared (LWIR) energy produced by a scene in the 8μm to 14μm waveband-into digital data that can be used to produce a visible image or be fed into a computer for interpretation. Because the thermal energy of a scene is independent of reflected light and because it can travel through obscurants with small particle sizes, thermal imaging is the technology of choice for imaging in the dark or other difficult environmental conditions.
Compound materials have made the headlines in recent semiconductor developments, which includes the Ohio-based researchers' new magnetic-semiconductor bi-layer of GaN and MnGa for spin control (which will operate at room temperatures), and to Intel and UCSB's development of a hybrid chip of light-emitting InP combined with silicon. But at this December's IEDM, one spotlight is on chalcogenide memories or phase change materials. Judging by patent activity, and some of the developments in 2006, this could become another ‘must have’ characteristic for advanced memories, though dates for wide availability range from 2008 to 2010.
It's an unusual sight to see conference delegates queuing in sunlight outside the Scottish Edinburgh Conference Centre. But the joint Electromagnetic Remote Sensing and Systems Engineering for Autonomous Systems meeting caused just such a logjam in processing its first-day's attendance of 550 delegates. It was also an unusual conference being the first such joint airing of disparate, but defence related research developments. And not the smallest part of its charm was that rather than featuring ‘hero’ devices and development; both the problems and progress were aired.
With the recent introduction of its new line of gallium nitride high-power amplifiers, RF Micro Devices®, Inc. (RFMD®) has provided a product family that can significantly upgrade the efficiency of cellular base stations and similar applications. In doing so, the firm has skillfully leveraged its existing manufacturing facility to produce the GaN amplifiers at marginal cost.
Silicon and III-V compound semiconductors generally don't mix and today's basic CMOS logic devices choose to use less expensive silicon. A new research effort aims at devices that use higher mobility III-V channels to meet future expectations for progress.
The International Microelectronics and Packaging Society (IMAPS) has begun a study of the two most widely used industry roadmaps, the International Technology Roadmap for Semiconductors (ITRS) and the roadmap of the International Electronics Manufacturing Initiative (iNEMI). Where ITRS is centred on technical chip-level challenges, the iNEMI roadmap addresses upcoming requirements at higher levels of integration.
At a research level SiC-based graphene, CVD grown CNTs, DNA directed ZnO nanowires, “wet” PbS semiconductor performance, UNCD and GaN-on-diamond devices, not to mention Ge pre-amorphised silicon, are all emerging to illuminate new compound material routes for next generation devices.
Electronic transport characterization in semiconductor materials is becoming increasingly difficult as multi-layer and multi-carrier materials become more common. Examples include multiply doped or compensated regions, doping non-uniformities perpendicular to the conduction plane, 2D carriers at surfaces and interfaces, heterostructures, multiple quantum well structures, and materials with carriers populating different conduction band minima or valence band maxima. The heterostructures can contain delta-doped layers only a few atoms thick sandwiched between many other layers. Knowledge of the transport properties of all carriers present can greatly aid understanding of new materials and devices, identifying processing problems, and reducing costs by identifying good material early in the fabrication process.
This update of an earlier feature looks over business and technical developments from the past year. Only a few years ago there were three times as many companies making VCSELs. Some industry observers think that the dozen or so around today is still too many. Indeed, consolidation continues and the sector has lost at least one or two names in the past year. Nevertheless, the VCSEL market is thriving thanks to investment and innovation.
Out of four new UK projects announced this year, which total £18.8m, three are focused on the use of optoelectronics and compound materials, and should put the ten participants well into the van of product development. The players are Gemfire awarded £1.7m; the Centre for Integrated Photonics, Bookham, Epichem, Loughborough Surface Analysis, the Universities of Sheffield, and Surrey sharing in £1.7m; and Compound Semiconductor Technologies (CST) Global, Renishaw Plc with Heriot-Watt University's Micro Systems Engineering Centre with £400,000.
One anniversary which must not pass by is that of fibre optics. Four decades on the technology continues to evolve and the business looks more encouraging than it has for a while. Fibre optics began life as a medical instrument but now is a multi-billion dollar industry which supports much of the III-Vs business.
Optoelectronic components have been responsible for a quiet revolution in manufacturing and related processes. Low power confers portability, while emission and detection at new wavelengths are filling the gaps in the spectrum. These are just some of the benefits manufacturers are deriving from photonics. Optoelectronics are improving existing processes and helping innovate new ones for a wide range of industries.
Low-cost silicon germanium technology is chasing indium phosphide heterojunction bipolar transistor performance. US researchers have pushed the cut-off frequency for SiGe HBTs to 500 GHz, but this is still about 200 GHz behind the best InP result so far.
One of the curiosities of today's industry is how few companies turn in a consistent profit. When looking over recent financials, it is striking how sales can be up but profitability remains elusive. The good news is that many say they are on the path out of the red ink. What they will be hoping is that the general growth remains positive. But we all know this by no means assured.
