Nanoscale lithographic technologies have been intensively studied for the development of the next generation of semiconductor manufacturing practices. While mask-less/direct-write electron beam (EB) lithography methods serve as a candidate for the upcoming 10-nm node approaches and beyond, it remains difficult to achieve an appropriate level of throughput. Several innovative features of the multiple EB system that involve the use of a thermionic source have been proposed. However, a blanking array mechanism is required for the individual control of multiple beamlets whereby each beamlet is deflected onto a blanking object or passed through an array. This paper reviews the recent developments of our application studies on the development of a high-speed massively parallel electron beam direct write (MPEBDW) lithography. The emitter array used in our study includes nanocrystalline-Si (nc-Si) ballistic electron emitters. Electrons are drifted via multiple tunnelling cascade transport and are emitted as hot electrons. The transport mechanism allows one to quickly turn electron beamlets on or off. The emitter array is a micro-electro-mechanical system (MEMS) that is hetero-integrated with a separately fabricated active-matrix-driving complementary metal-oxide semiconductor (CMOS) large-scale integration (LSI) system that controls each emitter individually. The basic function of the LSI was confirmed to receive external writing bitmap data and generate driving signals for turning beamlets on or off. Each emitted beamlet (10 × 10 μm²) is converged to 10 × 10 nm² on a target via the reduction electron optic system under development. This paper presents an overview of the system and characteristic evaluations of the nc-Si emitter array. We examine beamlets and their electron emission characteristics via a 1:1 exposure test.

The influence of an electric field on carbon nanotube (CNT) growth using hot-filament chemical vapour deposition is investigated. Acetylene (C₂H₂) gas diluted with hydrogen is used as the source gas for the growth of CNTs, and a bias voltage of -300 V is applied to the sample stage during growth. The silicon substrate onto which the CNT is grown is prepared by sputtering a thin catalysed metal (Ni) film onto the surface, and the CNT is selectively grown from the tip of a silicon protrusion on the substrate. It is found that the application of a high electrostatic field with a negative substrate bias enhances the growth of CNTs in this situation. This effect is successfully applied to the fabrication of a CNT tip supported by a silicon cantilever for use in scanning probe microscopy.

The nanomechanical properties of single-crystalline silicon cantilevers as resonating elements are investigated in ultra-high vacuum. Flash heating the single-crystalline silicon cantilever at $\text{1000\hspace{0.05em}°}\mathrm{C}$ in ultra-high vacuum dramatically reduced the mechanical energy dissipation of the oscillating cantilever due to the removal of contaminants and natural oxide and reconstruction of the silicon surface. However, the reconstructed silicon surface is not stable and mechanical properties change depending on the surface state. The Q-factor and influence of gas adsorption on ultrathin single crystalline silicon resonators having (100) and (111)-oriented surfaces are presented.

This article discusses the possibility of tunable RF surface-acoustic-wave (SAW) and bulkacoustic-wave (BAW) filters using varactors (VCs) integrated by the skillful use of micro-electromechanical system (MEMS) technologies. First, the reasons that RF tunable filters are in demand for current wireless communications are explored, and various RF tunable filters are surveyed and compared. Next comes a discussion of tunable RF SAW/BAW filters combined with MEMS technologies, showing that high performance can be expected, provided that some key technologies are developed. Finally, the article introduces tunable SAW filters, which the authors developed in a research project called "heterointegration" to demonstrate what is possible by combining MEMS technologies with RF SAW/BAW technologies.

We report on a device concept, results of fabrication, and characterization of a monolithic electron field emitter array with focus lenses for multielectron beam lithography and high-density nano data storage. An array of individually addressable emitters of various materials was patterned on oxidized etch pits of a silicon on insulator (SOI) wafer. Si active layer of the SOI with gate hole array that self-aligned with the emitters was used as a common gate electrode. An array of cylindrical holes formed at the Si base of the SOI was used as a common lens electrode. For a single Pt emitter with gate hole of 2 μm diameter, the emission current started at a gate voltage $V_{\mathrm{gate}}\text{=90\hspace{0.05em}}\mathrm{V}$ and reached to 1.2 μA current and 0.84 mW beam power at $V_{\mathrm{gate}}\text{=300\hspace{0.05em}}\mathrm{V}$ and anode voltage $V_{\mathrm{anod}}\text{=0.7\hspace{0.05em}}\mathrm{kV}.$ The emission current was found to be stable with a fluctuation smaller than 10%/h. The emitter-gate and emitter-lens leak currents were found to be less then 1% compared with the emission current. The focusing characteristic of the device was experimentally confirmed by observing emission patterns on a phosphor anode screen. A simulation work using a finite-element method has shown that the emitted electron beam with emission cone angle within 15° can be focused at a spot of 40 nm diameter and 200 μm focal length at a lens voltage $V_{\mathrm{lens}}\text{=−6\hspace{0.05em}}\mathrm{V}.$