We investigate the use of Raman spectroscopy to measure carrier concentrations in n-type GaSb epilayers to aid in the development of this technique for the nondestructive characterization of transport properties in doped semiconductors. The carrier concentration is quantified by modeling the measured coupled optical phonon-free carrier plasmon mode spectra. We employ the Lindhard-Mermin optical susceptibility model with contributions from carriers in the two lowest GaSb conduction-band minima, the Γ and L minima. Furthermore, we evaluate three conduction-band models: (1) both minima parabolic and isotropic, (2) the Γ minimum non-parabolic and isotropic and the L minima parabolic and isotropic, and (3) the Γ minimum non-parabolic and isotropic and the L minima parabolic and ellipsoidal. For a given epilayer, the carrier concentration determined from the spectral simulations was consistently higher for the ellipsoidal L minima model than the other two models. To evaluate the conduction-band models, we calculated the L to Γ electron mobility ratio necessary for the electron concentrations from the Raman spectral measurements to reproduce those from the Hall effect measurements. We found that the model with the ellipsoidal L minima agreed best with reported carrier-dependent mobility-ratio values. Hence, employing isotropic L minima in GaSb conduction-band models, a common assumption when describing the GaSb conduction band, likely results in an underestimation of carrier concentration at room temperature and higher doping levels. This observation could have implications for Raman spectral modeling and any investigation involving the GaSb conduction band, e.g., modeling electrical measurements or calculating electron mobility.

The five invited papers and 11 contributed papers in this special issue discuss topics such as process variation, device variability, hierarchical modeling tools, and address challenges such as device mismatch and SRAM noise margin variability.

Over the last decade, the world of semiconductors has broadened its horizon from More Moore to More than Moore. Some first hypothesized the end of Moore’s law and the beginning of a new era. They saw it as an OR gate while some saw it as a NOR gate. Since then it has been an AND gate as Moore’s law has continued to move down it’s persistent scaling path. Even if it fades, i.e. the end of More Moore, both will technologies will flourish. The reason is that More than Moore is complementary to More Moore semiconductor technology. More than Moore is largely made up of MEMS, which integrate microelectronics with micromechanical structures. Some include 3D packaging, LEDs, and Photovoltaic cells into the mix. In the future there are NEMS, or Nano-ElectricalMechanical-Systems. In all cases the use manufacturing methods and metrology evolved from semiconductors. Metrology is critical to all these technologies, because to make something, you must be able to measure it, and to do that you must be able to see it. This presentation examines the Strengths, Weaknesses, Opportunities and Threats (SWOT) for both classical semiconductor markets and these emergent technologies. It delves into how their technologies are evolving and the economic impact of this evolution. It addresses such questions as: • Is scaling measurably slowing? • Are design costs getting too high? • What are the critical factors for a Moore’s Wall scenario? • As chips become an ever big-player game, will there be enough research centers to support metrology development. • How fragmented is the More than Moore Market? • Who are the leading players? • Will they cross the valley of death from MEMS to Bioelectronics?

In 2007, the National Institute of Standards and Technology and the International Society for Clinical Densitometry designed a survey to prioritize 7 research and standardization action items to improve accuracy and cross-comparability of dual-energy X-ray absorptiometry (DXA) measurements of bone mineral density. In this article, we analyze the 1074 survey responses as one means to define consensus priorities of the community studying bone health and to determine possible correlations between prioritization and demographic data, including geographic location, years of experience practicing DXA, and medical specialty. We find that the distribution of ranks from all respondents is such that we can conclude with statistical confidence that there are perceived distinctions between the relative merits of the 7 action items. Applying a standard vote-counting rule to the data, we determine a complete ranking of the action items. We observe that a consistent ranking of each action item across all demographic subcategories is hard to achieve. When we arrange the 7 action items into 4 groups, however, we can determine a reasonably consistent prioritization. The group containing the development of standard reference databases and phantoms receives the highest priority. In addition, we report consistent themes that emerge from the free-response portion of the survey.

In 2006, the National Institute of Standards and Technology conducted an assessment of the U.S. measurement system (USMS), which encompasses all private and public organizations that develop, supply, use, or ensure the validity of measurement results. As part of that assessment, NIST collaborated with Energetics Incorporated to identify and authenticate 723 measurement needs that are barriers to technological innovations. A number of these measurement needs (64) are relevant to accelerating innovation and commercialization of nano-electrotechnologies. In this paper, we apply the taxonomy from a 2008 international survey that established a global consensus of priorities for standards and measurements in nano-electrotechnologies to rank in priority order the relevant 64 USMS-identified measurement needs. This paper presents a method for assigning priorities that is statistically based and represents a global consensus of stakeholders. Such a method is needed because limited resources exist to address the large number of measurement needs in nano-electrotechnologies, and the most critical measurement needs should be addressed first.

In 2008, the National Institute of Standards and Technology and Energetics Incorporated collaborated with the International Electrotechnical Commission Technical Committee 113 (IEC TC 113) on nano-electrotechnologies to survey members of the international nanotechnologies community about priorities for standards and measurements to accelerate innovations in nano-electrotechnologies. In this paper, we analyze the 459 survey responses from 45 countries as one means to begin building a consensus on a framework leading to nano-electrotechnologies standards development by standards organizations and national measurement institutes. The distributions of priority rankings from all 459 respondents are such that there are perceived distinctions with statistical confidence between the relative international priorities for the several items ranked in each of the following five Survey category types: 1) Nano-electrotechnology Properties, 2) Nano-electrotechnology Taxonomy: Products, 3) Nano-electrotechnology Taxonomy: Cross-Cutting Technologies, 4) IEC General Discipline Areas, and 5) Stages of the Linear Economic Model. The global consensus prioritizations for ranked items in the above five category types suggest that the IEC TC 113 should focus initially on standards and measurements for electronic and electrical properties of sensors and fabrication tools that support performance assessments of nano-technology enabled sub-assemblies used in energy, medical, and computer products.

We demonstrate quantitatively how values of electron densities in GaAs extracted from Raman spectra of two samples depend on models used to describe electric susceptibility and band structure. We, therefore, developed a theory that is valid for any temperature, doping level, and energy ratio proportional to q 2=(ω + iγ) (where q is the magnitude of wave vector, ω is Raman frequency, and γ is plasmon damping). We use a full Mermin-Lindhard description of Raman line shape and compare n-type GaAs spectra obtained from epilayers with our simulated spectra. Our method is unique in two ways: (1) we do a sensitivity analysis by employing four different descriptions of the GaAs band structure to give electron densities as functions of Fermi energies and (2) one of the four band structure descriptions includes bandgap narrowing that treats self-consistently the many-body effects of exchange and correlation in distorted-electron densities of states and solves the charge neutrality equation for a two-band model of GaAs at 300 K. We apply these results to obtain electron densities from line shapes of Raman spectra and thereby demonstrate quantitatively how the values of electron densities extracted from Raman spectra of n-type GaAs depend of various models for susceptibility and band structure.

We discuss the ability of the nation’s measurement system to meet future metrology needs of the semiconductor industry. Lacking an acceptable metric for assessing the health of metrology for the semiconductor industry, we identify a limited set of unmet measurement needs. Assuming that this set of needs may serve as proxy for the galaxy of semiconductor measurement needs, we examine it from the perspective of what will be required to continue the semiconductor industry’s powerful impact in the world’s macro-economy and maintain its exceptional record of numerous technological innovations. This paper concludes with suggestions about ways to strengthen the measurement system for the semiconductor industry.

The special issue consists of 25 papers, five of which are invited and 20 of which are contributed, that discuss topics such as process modeling, device modeling, and atomistic modeling, and address issues like reliability, manufacturability, and variability. The papers are briefly summarized here.

Radio frequency (RF) and analog/mixed-signal (AMS) integrated circuits (ICs) are key enabling components for mobile and wireless communications and their advancements continue to drive the growth of the related semiconductor market. The circuit and technology requirements for RF and AMS ICs in mobile and wireless communications are quite different in comparison to that for digital logic and memory applications. Many tradeoffs and unique considerations have to be applied for RF and analog/mixed-signal technology development and circuit implementations. This paper reviews the critical circuit and technology requirements for RF and analog/mixed-signal ICs for mobile and wireless communications and highlights future challenges and opportunities

This article reports and discusses the results of the recent ISCD-NIST Workshop on Standards and Measurements for Assessing Bone Health. The purpose of the workshop was to assess the status of efforts to standardize and compare results from dual-energy X-ray absorptiometry (DXA) scans, and then to identify and prioritize ongoing measurement and standards needs.

The International Technology Roadmap for Semiconductor (ITRS) Radio Frequency and Analog/Mixed-Signal (RF and AMS) Wireless Technology Working Group (TWG) addresses device technologies for wireless communications covering both silicon and III-V compound semiconductors. This paper discussed the roadmap and the figures of merit (FoM) used to characterize both active and passive devices critical for typical radio front end designs. The trends, challenges and potential solutions was reviewed and address the intersection of silicon and III-V compound semiconductors

Wireless applications have grown quickly to become significant markets for compound semiconductor device manufacturers. As a result, the 2003 ITRS recognizes wireless applications enabled by RF and analog/ mixedsignal (AMS) devices as a separate new system and technology driver. A technology roadmap for RF and AMS applications of compound semiconductors now exists in the 2003 International Technology Roadmap for Semiconductors (ITRS). Past ITRS roadmaps focused on mainstream CMOS and BiCMOS processes and applications. For the first time, the current 2003 ITRS Roadmap includes III-V compound semiconductors in the context of CMOS technology nodes. We present selected highlights from the 2003 ITRS that concern compound semiconductors and suggest possible implications for the Compound Semiconductor MANufacturing TECHnology community.