Beyond Feynman’s Dreams
Frontiers of Nanotechnology
ISHIUCHI Hidemi / ITOH Yoshiyasu / INABA Michihiko
A wide variety of applications have been developed as outcomes of the nanotechnology revolution. Examples in the energy engineering field include nanostructure ceramics, power generation systems using nanocrystals, while examples in the electronics field include the development of semiconductor integrated circuits with a feature size in the sub-hundred nm range, and nanosize semiconductor devices such as quantum dots and single-electron transistors, and so on. Measurement techniques are progressing as well. In addition to physical and chemical methods, biochemical methods using DNA molecules as probes have also been developed.
Nanotechnology is expected to become a major driver of innovation in the near future.
Thermoelectric Generating System for Effective Use of Unutilized Energy
SHINDO Takahiko / NAKATANI Yujiro / OISHI Takashi
Exhaust heat with a low temperature of 150°C or less exists in large quantities. However, the thermal energy cannot be used efficiently from both the economic and technical points of view. For efficient collection of this thermal energy, Toshiba has developed a thermoelectric module with a bismuth-tellurium composition, a thermoelectric system using the module, and long-term reliability evaluation technology for the module. The thermoelectric module with a nanocrystalline structure showed a conversion efficiency of 3.6% at 130°C, exceeding that of conventional materials. In addition, we confirmed the high reliability of the thermoelectric module through a study conducted at a geothermal generation system in the Kusatsu hot springs area as well as by a heat-cycle evaluation study.
Nanostructured Joining Technology for High-Strength Reaction-Sintered Silicon Carbide
SUYAMA Shoko / ITOH Yoshiyasu
High-strength reaction-sintered silicon carbide (SiC) developed by Toshiba has the world’s highest strength, exceeding 1,000 MPa, and properties such as no pores, almost no sintering shrinkage, and low sintering temperature. However, joining technology is indispensable for this material in order to apply it to components of large size and complex shape.
We have therefore developed a nanostructured joining technology for high-strength reaction-sintered SiC that realizes excellent thermal stability and high joining strength. We are now in the process of applying this technology to hydrogen production systems and space optics.
Nanosensing Technique Using X-ray Color Image Intensifier
NITTOH Koichi / MIYABE Keisuke / NAKAYAMA Kunihiko
Nondestructive photography of high-speed phenomena is required in a broad range of leading-edge technologies such as the analysis of collision phenomena of solids and liquids and the inspection of vibration and distortion under high-speed operation. In addition, minute observation at the nanometer scale is essential for many basic technologies such as the microfabrication of electronic parts and machines, crack inspection of materials, and development of functional materials.
The Color I.I.TM (UltimageTM) color image intensifier, originally developed as an X-ray real-time imaging device, has various advantages in terms of high-speed and precise imaging compared with other devices. The Color I.I.TM system can take high-speed X-ray transmission images in the range of tens of nanoseconds, which is not possible using film- or imaging plate (IP)-based systems. Furthermore, a spatial resolution as small as 400 nm can be attained by the combination of the image-magnifying function of the Color I.I.TM system, a high-resolution camera, and an X-ray source of 400 nm focus size.
25 nm SONOS Type Memory Device Using Double Tunnel Junction
A 25 nm gate length bulk-planar silicon oxide nitride oxide semiconductor (SONOS) type memory, which has a Si nanocrystalline layer between double tunnel oxides, shows excellent memory characteristics due to the Coulomb blockade and quantum confinement functions of Si nanocrystals.
Toshiba has experimentally shown direct evidence of the great advantage in trade-off between charge retention and write/erase (w/e) speed using this device, suggesting that further device scaling and improvement are possible by Si nanocrystal size scaling. We have been developing the double tunnel junction SONOS type memory as a strong candidate for use in the smaller than 25 nm region.
New Nanoarchitectures for Post-CMOS Era
FUJITA Shinobu / ABE Keiko / YASUDA Shinichi
The complementary metal-oxide semiconductor (CMOS) based on the silicon metal-oxide semiconductor field-effect transistor (Si-MOSFET) may reach its limit within 10 years. However, no new solution has been proposed yet for the post-CMOS era.
Toshiba has been working on building new nanoarchitectures for the post-CMOS era using the most realistic methods possible. For this purpose, we have developed new circuitry using post-silicon memory and transistors, three-dimensional (3D) circuitry, fault-tolerant circuitry, network circuitry, and so on. Among these, the design of high-bandwidth 3D memory and fault-tolerant circuitry is the most important.
Bit-Cost Scalable Technology for Low-Cost and Ultrahigh-Density Flash Memory
TANAKA Hiroyasu / AOCHI Hideaki / NITAYAMA Akihiro
Toshiba has been developing bit-cost scalable (BiCS) technology to realize low-cost and ultrahigh-density flash memory. A feature of BiCS technology is that a whole stack of electrode plates is punched through and plugged by another material to form a three-dimensional memory cell array. This fabrication process is expected to achieve a continuous reduction in bit-cost, since the number of processes will not significantly rise against increases in the number of layers for future ultrahigh-density memories.
Technologies for RF MEMS Tunable Capacitors
OHGURO Tatsuya / IKEHASHI Tamio / SUGIZAKI Yoshiaki
In recent years, cellular phones have become capable of handling not only wideband code division multiple access (W-CDMA) but also one-segment TV broadcast reception, the Suica card payment system, and FM radio. Furthermore, many functions are being added for better communication such as Bluetooth®, ultra-wideband (UWB), worldwide interoperability for microwave access (WiMAX), wireless LAN (WLAN), and so on. In order to balance the increase of components for broadband and miniaturization of terminals, radio-frequency microelectromechanical system (RFMEMS) variable capacitors have been attracting considerable attention. However, it is necessary to overcome the problems of stiction of the MEMS actuator and the fact that MEMS packaging technology has not yet been fully established.
In response to these problems, Toshiba has developed an intelligent driver integrated circuit (IC) realizing stable operation of the MEMS actuator and an in-line wafer level package (WLP) technology with high reliability and low cost.
Electrochemical DNA Chip for Personalized Medicine
GEMMA Nobuhiro / HASHIMOTO Koji / NIKAIDO Masaru
Toshiba has developed an electrochemical DNA chip that makes simple and low-cost DNA testing possible due to the realization of a compact detection system and elimination of the need for dye labeling. The electrochemical DNA chip is expected to become a platform in the medical diagnostic field in place of the conventional fluorescent DNA chip.
For personalized medical care, we have established a highly accurate system using electrochemical DNA chips to predict response to interferon in patients with the hepatitis C virus (HCV) and to detect single nucleotide polymorphisms (SNPs) indrug metabolizing euzyme genes. We have also been developing future technologies such as a fully automated DNA detection system and a complementary metal-oxide semiconductor (CMOS) type DNA chip.
Bioassay for Detecting Neurotoxicity of Environmental Contaminants
SUGANO Mitsuko / AKAHOSHI Eiichi / URUNO Saeko
Various environmental chemicals are suspected to damage human health. An adequate method of assessing the toxicity of such chemicals has not yet been established, however, because they affect different organs such as the liver, reproductive organs, immune tissues, nervous tissues, and so on.
Toshiba has developed a tyrosine hydroxylase (TH) assay method for detecting the neurotoxicity of environmental contaminants. This is an in vitro bioassay method using TH gene expression, which is a functional marker of the dopamine system in the brain, together with evaluation metrics. TH assay provides a simple screening method with high throughput for a large number of environmental contaminants.