森田 昇

<p>FIB加工によって単結晶ダイヤモンド表面に変質層が形成される．本研究では，顕微ラマン分光法を用いて，深紫外光照射による加工変質層の構造変化の過程に着目する．酸素雰囲気中において深紫外線照射することによって，加工変質層のエッチングが観測される．その酸素濃度依存がエッチング速度に影響を及ぼすことを明らかにした．発表では，深紫外光照射による加工変質層の構造変化のプロセスについて，およびエッチング後の表面構造について考察する.</p>

本研究では，電圧印加を併用したイオン交換処理により，ガラス中に金属微粒子を分散させ，ガラスのレーザ加工特性の向上を試みた．作製したガラスの吸収率は可視域において大きな変化は見られず，紫外域において大きな増加が認められた．また，ナノ秒YAGレーザの第4高調波を用いてレーザ加工実験を行った結果，加工底面に割れや欠けの見られない良好な加工を行うことができ，レーザ加工特性の向上が認められた．

In various fields of nanotechnology, the importance of nanoscale three-dimensional (31)) structures is increasing. In order to develop an efficient process to fabricate nanoscale 3D structures, we have applied highly charged ion (HCI) beams to the ion-beam lithography (IBL) technique. Ar-ion beams with various charge states (1 to 9+) were applied to fabricate spin on glass (SOG) and Si by means of the IBL technique. The Ar ions were prepared by a facility built at Kochi University of Technology, which includes an electron cyclotron resonance ion source (NANOGAN, 10 GHz). IBL fabrication was performed as a function of not only the charge state but also the energy and the dose of Ar ions. The present results show that the application of an Ar9+ beam reduces the etching time for SOG and enhances the etching depth compared with those observed with Ar ions in lower charged states. Considering the high-energy deposition of HCI at a surface, the former phenomena can be understood consistently. Also, the latter phenomena can be understood based on anomalously deep structural changes, which are remarkable for glasses. Furthermore, it has also been shown that the etching depth can be easily controlled with the kinetic energy of the At ions. These results show the possibilities of the IBL technique with HCI beams in the field of nanoscale 3D fabrication. (C) 2008 American Institute of Physics.

Atomic force microscopy (AFM) was originally developed for atomic resolution surface topography observations. Nowadays, it is also widely used for nanolithography. AFM-based lithography is an effective method compared to conventional photolithographic processes due to its simplicity, high resolution, and low cost. It can provide nanoscale stage control and the probing tip can be used as a lithographic tool. Therefore, various AFM-based nanoscale fabrication methods have been proposed using electrochemical oxidation, material transfer, mechanical lithography, and thermally induced modifications. This chapter will introduce the detailed processes and applications of AFM-based lithographic techniques.

In this study, we developed precision processing equipment that has processing mechanism by a shaper system and a milling system. Precision processing mechanism by a shaper system has an edge of a CVD diamond on the tip of a cantilever for frictional force microscopes (FFM). And precision milling mechanism has an edge of a pyramidal CVD diamond on the tip of a spindle. This equipment can do processing and the measurement in ranges from nanometers to micrometers. This report will introduce about the concept and mechanism of this equipment.

Nano-scale fabrication of silicon substrate based on the use of atomic force microscopy (AFM) was demonstrated. A specially designed cantilever with diamond tip allows the formation of damaged layer on silicon substrate by a simple scratching process. A thin damaged layer forms in the substrate along scanning path of the tip. The damaged layer withstands against wet chemical etching in aqueous KOH solution. Diamond tip acts as a patterning tool like mask film for lithography process. Hence these sequential processes, called tribo-nanolithography, TNL, can fabricate 2D or 3D micro structures in nanometer range. This study demonstrates the fabrication processes of the micro cantilever and diamond tip as a tool for TNL. The developed TNL tools show outstanding machinability against single crystal silicon wafer. Hence, they are expected to have a possibility for industrial applications as a micro-to-nano machining tool.

This study proposes a novel method of nano-scale patterning on a metallic glass surface using focused ion beam (FIB) irradiation followed by wet chemical etching. We found that etch rate of a metallic glass surface irradiated with Ga+ion beam can be drastically changed, and rapid patterning is possible utilizing this method. Cross-sectional transmission electron microscopy (TEM) analysis reveals that the metallic glass substrate remains amorphous phase after the irradiation. In addition, etching enhancement does not shown at the irradiation of Ar+ions. Thus, these results indicate that the etching enhancement is resulted from the existence of implanted Ga+ion rather than the change in crystallization.

Etching characteristics of a silicon surface irradiated by high-energy ion beam against HF are investigated in this study. Specially designed ion irradiation facility, which enables to irradiate high-energy ion beam, is employed. A deep structure with a depth of several hundreds nanometers can be fabricated by utilizing high-energy ion irradiation. The depth of irradiated area can be controlled by adjusting acceleration voltage and ion charge, and it is related to distribution of damaged layer induced by ion irradiation. These results indicate a possibility of application as a novel deep three-dimensional nanofabrication process.