Three-dimensional nanostructure fabrication has been demonstrated by 30 keV Ga+ focused ion beam assisted deposition using a aromatic hydrocarbon precursor. The characterization of deposited film on a silicon substrate was performed by a transmission microscope and Raman spectra. This result indicates that the deposition film is a diamondlike amorphous carbon. Production of three-dimensional nanostructure is discussed. Microcoil, drill, and bellows with 0.1 μm dimension were fabricated as parts of the microsystem. Furthermore, microstructure plastic arts is advocated as a new field using microbeam technology, presenting one example of a microwine glass with 2.75 μm external diameter and 12 μm height.

A nonpolymer material, calixarene derivative (hexaacetate p-methnylcalix[6]arene) was tested as a high-resolution negative resist under an electron beam lithography process. It showed under 10-mm resolution with little side roughness and high durability to halide plasma etching. A sub-10-nm Ge quantum wire was perfectly etched off without defects. Such a performance is suitable for nanoscale device processes.

The Morpho-butterfly wing reflects interfered brilliant blue, which originates from nanostructures on its scales, for any incidence angle of white light. We have, for the first time, fabricated a Morpho-butterfly-scale quasi-structure using focused-ion-beam chemical-vapor-deposition (FIB-CVD) and observed brilliant blue reflection from this quasi-structure with an optical microscope. We measured the reflection from real Morpho-butterfly scales and from the quasi-structure with a photonic multi-channel spectral analyzer system. The reflection spectra of the quasi-structure were very similar to those of Morpho-butterfly scales.

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The current state of focused ion beam (FIB) applications in relation to solid state devices is reviewed, and recent use of FIB technology for lithography, etching, deposition, and doping are described. Etching and deposition have become essential processes for failure analysis and for mask repair in silicon ULSL production. Furthermore, the FIB doping technique has been used to fabricate quantum effect devices.

Focused-ion-beam chemical vapor deposition (FIB-CVD) is an excellent technology for forming three-dimensional nanostructures. Various diamond-like-carbon (DLC) free-space-wirings have been demonstrated by FIB-CVD using a computer-controlled pattern generator, which is a commercially available pattern generator for electron-beam (EB) lithography. The material composition and crystal structure of DLC free-space-wiring were studied by transmission-electron microscopy and energy-dispersive x-ray spectroscopy. As a result, it became clear that DLC free-space-wiring is amorphous carbon containing a Ga core in the wire. Furthermore, the electrical resistivity measurement of DLC free-space-wiring was carried out by two terminal electrodes. Au electrodes were fabricated by EB lithography and a lift-off process. The electrical resistivity was about 100 Ω cm at room temperature.

Nanoimprint lithography is an attractive technology for LSIs era below 40-nm critical dimension from the viewpoints of high-throughput and low-cost equipment. In order to avoid a pattern placement error due to thermal expansion in the conventional thermal imprint process, we attempted to replicate the mold pattern onto a liquid polymer, which was solidified using ultra-violet (UV) light irradiation at room temperature. The liquid polymer used here was supplied by TEIJIN SEIKI Co., and termed TSR-820. It was spin coated on slide glass to produce approximately 1.5-µm-thick polymer film. The thickness remained after UV exposure and rinsing in acetone was observed at the dose of 10 J/cm 2 and it saturated about a UV exposure dose of 100 J/cm 2 with an increase in the exposure dose. The mold fabricated of quartz plate was first pressed onto the polymer film at about 100 kg/cm 2 and then the UV light was irradiated using an imprint apparatus developed for this work. After releasing the mold from the film, the substrate was rinsed in acetone to remove the residual liquid polymer. Eventually the minimum feature size of 100-nm line and 300-nm space pattern was successfully replicated in the polymer with good fidelity.

Enhancement of breakdown voltage (BV) with the increase of AlN buffer layer thickness was observed in AlGaN∕GaN high-electron-mobility transistors (HEMTs) grown by metalorganic chemical vapor deposition on 4in. Si. The enhancement of device performance with AlN buffer thickness (200 and 300nm) is due to the reduction of electrically active defects from Si substrate. The reduction of defects from Si with the increase of AlN thickness was confirmed by x-ray rocking curve measurements. Not much change has been observed in ON-state BV (BV:ON) values except in devices with 500-nm-thick buffer layer. About 46% enhancement in OFF-state BV (BV:OFF) was observed on 200μm wide HEMTs with 300nm thick AlN buffer layer when compared to HEMTs with 8nm thick AlN buffer layer. The location of junction breakdown in the device was identified as GaN∕AlN∕Si interface. The measured specific on-resistance (Ron) values for 200 and 400μm wide HEMTs with 300nm thick buffer layers were 0.28 and 0.33mΩcm2, respectively. About an order of low Ron was observed when compared with the reported values. The AlGaN∕GaN HEMTs on 4in. Si with thicker AlN buffer layers are suitable for high-power applications.