Yasuhiko Sugiyama

High-Precision Quadrupole Correction Lens for Ion-Beam Focusing: Design and Test of Multistage Self-Aligned Quadrupole Correction-Lens System

A multistage self-aligned quadrupole correction lens, which consists of two lens casings, is developed. Each lens-casing cylinder consists of three quadrupole and two aperture electrodes. All lens components in lens-casing cylinders are fabricated to achieve an electrode alignment accuracy better than 1 µm. Azimuth errors between entrance and exit lens-casing cylinders can be corrected using the rotary flange fastened to the entrance lens-casing cylinder. The correction-lens system is installed as the probe-forming objective lens in place of the rotationally symmetrical objective lens of the focused ion-beam system. Simulation results show that a four-stage quadrupole correction lens is useful as a correctable probe-forming objective lens because all aperture aberration coefficients can be effectively corrected under the condition of relatively low chromatic aberration. Probe-forming properties and beam shape affected by aperture aberrations of the four-stage quadrupole correction-lens system are observed by scanning ion microscope images.

Deposition Yield and Physical Properties of Carbon Films Deposited by Focused-Ion-Beam Chemical Vapor Deposition

The deposition yield and physical properties of carbon films fabricated by focused-ion-beam (FIB) chemical vapor deposition were examined using several ion beam species of hydrogen, helium, xenon, and gallium. A gas-FIB was generated using an inductively coupled plasma ion source. It was found that the deposition yield is proportional to the total stopping power of the beam that penetrates into the carbon film. The physical properties of the carbon films deposited using gas-FIB are similar to those of films deposited using Ga-FIB, except for the Youngs modulus.