An integrated slider-suspension system was designed and prototyped. The structure of this system has a full flying air-bearing surface in the leading part with a contamination-resistant feature, and it accommodates a slider with a 5-15 nm head-disk spacing at the trailing part. Performance analysis and simulation were conducted to validate the high performances of the design. Two key issues, the rigid motions (vibrations) and the elastic motions of the slider, were investigated systematically. For the rigid motions, it was found that the natural frequencies of the slider system are dependent on the disk contact stiffness and that the slider vibrations under excitation exhibit various nonlinear resonance. For the elastic motions, the average elastic response of the slider body under the random interaction of the interface was derived and characterized.

The growing availability of commercial foundry processes allows easy implementation of micro-opto-electro-mechanical systems (MOEMS) for a variety of applications. Such applications go beyond single devices to include whole optical systems on a chip, consisting of mirrors, gratings, Fresnel lenses and shutters, for example. Hinged and rotating structures, combined with powerful and compact thermal actuators, provide the means for positioning and operating these optical components. This paper presents examples of such systems built in a commercial polycrystalline silicon surface-micromachining process, the ARPA-sponsored Multi-User MEMS ProcesS (MUMPS). Examples range from optical sub-components to large mirror arrays, communication components, and micro-interferometers. Using the examples discussed in this paper, a designer can take advantage of commercially available surface-micromachining processes to design and develop MOEMS without the need for extensive in-house micromachining capabilities.

Micromechanisms and actuators which are 10-100 micrometers in size are studied by research groups in universities, national research institutes, and private industries in Japan. Some of them belong to a "Micromachine Technology" project lead by MITI (Ministry of International Trade and Industries). Microfabrication technologies based on both IC-compatible processes and mechanical machining are under development. Application-oriented devices in automobile, communication and information industries are also investigated. The research goal is to build a smart micro system through the integration of moving mechanisms, sensors and electronics on a chip; this is the fusion of mechanics and electronics in the microscopic world. This paper reviews recent activities in MEMS research in Japan.

The present paper describes a novel approach to interconnecting and assembling components of MEMS at room temperature. The main drawback of the conventional bonding methods is their rather high process temperatures. The new method, which is referred as the surface activated bonding (SAB), utilizes the phenomena of the adhesion between two atomically clean solid surfaces to enable the bonding at lower temperature or even at room temperature. In the bonding procedure, the surfaces to be bonded are merely brought into contact after sputter-cleaning by Ar fast atom in ultrahigh vacuum conditions. TEM observations of the bonded interfaces show that a direct bonding in atomic scale is achieved in the interface between the micro-components. Based on the concept of this new bonding technology, a micro-assembly system was developed. The micro-assembly system is operated by means of a virtual manipulation system in which 3D model of the micro-components are manipulated virtually in a computer graphics constructed in the world wide web (WWW) scheme. The micro-assembly system will provide a new design tool of three dimensional MEMS by combining the possibility of the flexible assembly and the intuitive operations.

GaAs-based micromachining is a very attractive technique for integrating mechanical structures and active optical devices, such as laser diodes and photodiodes. For monolithically integrating mechanical parts onto laser diode wafers, the micromachining technique must be compatible with the laser diode fabrication process. Our micromachining technique features three major processes: epitaxitial growth (MOVPE) for both the structural and sacrificial layers, reactive dry-etching by chlorine for high-aspect, three-dimensional structures, and selective wet-etching by peroxide/ammonium hydroxide solution to release the moving parts. These processes are compatible with laser fabrication, so a cantilever beam structure can be fabricated at the same time as a laser diode structure. Furthermore, a single-crystal epitaxial layer has little residual stress, so precise microstructures can be obtained without significant deformation. We fabricated a microbeam resonator sensor composed of two laser diodes, a photodiode, and a micro-cantilever beam with an area of 400700 µm. The cantilever beam is 3 µm wide, 5 µm high, and either 110µm long for a 200-kHz resonant frequency or 50 µm long for a 1-MHz resonant frequency. The cantilever beam is excited by an intensity-modulated laser beam from an integrated excitation laser diode; the vibration signal is detected by a coupled cavity laser diode and a photodiode.