The improvement in the performance of Si Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) through conventional device scaling has become more difficult, because of several physical limitations associated with miniaturization. In this paper, new CMOS device technologies using high-mobility/velocity channels, which have attracted much attention as a booster for device performance, are reviewed. The device physics underlying this channel engineering for improving the drive current of MOSFETs with short channels is summarized from the viewpoint of electronic states of carriers in inversion layers and, in particular, the optimum design of subband structures. In addition, recent experimental results for MOSFETs using strained Si, Ge, ultrathin body channels are described.

Recently, double-gate (DG) MOSFETs have received considerable interest as promising candidates for future ULSI circuits. In this article, the history and present status of the DG MOSFETs are reviewed. The possible development of a new DG MOSFET technology is also discussed.

For the reduction in the active power consumption of ULSI devices, a decrease in the parasitic capacitance in multilevel interconnects for ULSI must be realized by introducing low-k dielectric films corresponding to CMOS scaling. In a 90 nm-node ULSI, a low-k film with k=3.0 is introduced by controlling the chemical composition of a conventional silica film to reduce electron polarization. For a 65 nm-node ULSI and beyond, the dielectric constant is reduced effectively by inserting sub-nanometer-sized pores into the dielectric films. In this report, the process integration technology for ULSI interconnect with porous film, as well as sophisticated pore structural control technology on the molecular scale, are described.

In decreasing the power consumption in LSIs, the reduction in gate insulator thickness is indispensable. Because the gate oxide thickness decreases to 1 nm or below in the next generation, gate leakage current increases and becomes unacceptable for transistors. To eliminate gate depletion, metal gates are used, because they eliminate a gate depletion layer. In this paper, the historical background of the development of gate electrodes and the present status and issues of metal gates are discussed.

Immersion lithography with 193 nm light and purified water is rapidly becoming a realistic method for semiconductor production. In the development history of this technology since 2002, most issues are solved by fluid dynamic simulation and experiments. Local-fill configuration was experimentally demonstrated as the most promising method for water retaining. At present, full-field exposure tools of NA=0.85 are operating and generating a good imaging data as expected for immersion lithography. The most current issue is pattern defectivity on a resist, which is being improved with an optimized resist process. We believe, in the near future, that NA=1.30 immersion optics with purified water will realize half-pitch 45 nm imaging.

Since the 1980s, organic semiconductors have been actively pursued for organic field-effect transistors (OFETs). In this report, first we review the recent development of OFET materials including hole and electron transport materials. Then we show a well-defined concept of ambipolar transport properties in OFETs. Ambipolar FET behaviors are observed using conventional organic semiconductors, such as pentacene and phthalocyanine, which have been considered to behave as p-type organic semiconductors.

The role of a third-generation synchrotron radiation facility, such as SPring-8, is becoming increasingly important for the research of the structure-property relationship of novel functional materials. Particularly, powder diffraction is currently considered a very powerful tool for a precise charge density study by the development of a maximum entropy method (MEM)/Rietveld method. The recent results of direct observation of hydrogen in materials and charge ordering of EDF-TTF molecules associated with metal-insulator phase transition are described to illustrate the possibility of an accurate structure-property study using a synchrotron radiation diffraction method at SPring-8.

One of the dominant themes in the quest for new or high-performance functional materials is scale reduction. A reduction in feature size has long been a driving force in the development of magnetic media, for example, and has led to the well-documented exponential increase in real storage density. A new class of functional units known as “sandwich nanoclusters” is being studied in gas phase synthesis using laser vaporization. The multilayer sandwich nanoclusters may serve as molecular building blocks in highly anisotropic thin-film materials. A key requirement to achieving thin-film functional materials is the production of a substrate capable of supporting spatially oriented sandwich nanoclusters in a patterned array using a soft-landing technique.

HfO₂-based materials are considered the most promising candidate for high-k gate dielectrics of next-generation metal oxide semiconductor field-effect transistors (MOSFETs). To introduce these new materials into advanced MOSFETs, a clear understanding of the reliability physics is indispensable. In this article, the effects of holes and oxygen defects on time-dependent dielectric breakdown (TDDB), stress-induced leakage current (SILC) and bias temperature instability (BTI) are discussed, on basis of the results of both experimental and theoretical investigations.

Although Si-LSI technology has achieved high-speed and low-power-consumption devices by device shrinkage, there is a possibility that the device shrinkage will encounter difficulties. Thus, next-generation LSI technology requires an alternative method of achieving high-performance devices. A strained Si/SiGe heterostructure has a large potential, because Si on strain-relaxed SiGe receives tensile strain, causing the enhancement of carrier mobility. We have demonstrated a 200 mm strained-Si wafer fabrication technique. In this report, we introduce this fabrication technique and the electrical properties of the fabricated wafer. A test circuit was also fabricated to characterize the quality of the strained Si wafer. In addition, we introduce a technique of enhancing the strain relaxation of a SiGe virtual substrate on SiO₂.

Positron annihilation is an established technique for investigating vacancy-type defects near surfaces or interfaces. Using this technique, one can identify defect species in a nondestructive manner. Because there is no restriction of sample conductivity or temperature, this technique can be applied to a various materials, such as semiconductors, metals, metal oxides, and polymers. The positron annihilation has been applied to the studies of Si-technology related materials, which show that it can provide useful information for the development of semiconductor devices. In this article, we report the results obtained for electroplated Cu, strained Si and high-k materials.

It is well known that diamond as a semiconductor has a high potential for electronic device applications. Over the last decade, research studies on diamond films for electronic device applications have progressed in terms of both issues of material and fabrication process relations. In this paper, recent achievements in CVD diamond films for electronic devices are reviewed in terms of homoepitaxial growth, film quality, doping, surface properties, and interface and simple device performance characterizations.

Recently, an extraordinary development in molecular biology has led to the discovery of various novel drugs. Simultaneously, a technology for optimizing the therapeutic effects of drugs, which is named the ‘drug delivery system (DDS)’, has been attracting considerable attention. A novel DDS, which is developed using physicochemical, chemical, and biological approaches, has various smart functions for maximizing the therapeutic efficacies of drugs. Herein, we review recent developments in DDS research studies, referring to clinically available formulations. Particular focus is placed on the design of a DDS with integrated smart functions.

The concept of a strained quantum well (QW) utilizing an intentional lattice mismatch to a substrate material opened a door to a new era of material design for optoelectronic devices. As a consequence, almost all semiconductor laser characteristics, such as threshold current, output power, their temperature dependences and so on, were markedly improved during the 1990s. The typical features of the strained QW are reviewed from the viewpoint of device performance.