Moonkeun KimBeomseok HwangYong-Hyun HamJaehwa JeongNam Ki MinKwang-Ho KwonKorea UniversityDepartment of Control and InstrumentationEngineeringChungnam 339-700, Republic of KoreaE-mail: kwonkh@korea.ac.krAbstract. Wecompare the performances of vibration-powered microelec-tromechanical system (MEMS) electrical generators using a PbðZr;TiÞO

Design, fabrication, and experimental demonstration of a piezoelectric cantilever for a low resonant frequency microelectromechanical system vibration energy harvester

The use of a PtOx thin film as a transient template of Pt electrode in the fabrication of ferroelectric capacitor for memory devices was investigated. Fence-free patterning with a significantly high etch rate, selectivity, and sidewall slope was obtained from dry etching the photoresist-masked PtOx films using Ar/Cl2/O2 helicon wave plasma. The x-ray photoelectron spectroscopy analysis indicates that the redeposition of PtClx etch product can be repressed due to an in situ sidewall passivation with a PtO2 layer resulting from a further oxidation of the etched surface of PtOx film by the introduction of oxygen in the etching gas. Due to the chemical instability of oxygen in the PtOx film, a superior hydrogen blocking effect was also achieved in hydrogen plasma annealing of the Pb(Zr0.5Ti0.5)O3 (PZT) ferroelectric capacitors with the use of PtOx as the top electrode, and the hydrogen degradation of the PZT capacitor was repressed.

Plasma etching and hydrogen blocking characteristics of PtOx thin films in ferroelectric capacitor fabrication

In this work, we propose a flash light-assisted facile and eco-friendly synthesis technique for Pt-based alloy nanoparticle/carbon nanotube catalysts. Pt and Pt-Ru alloy nanoparticle/multiwalled carbon nanotube (MWCNT) catalysts could be directly fabricated in a few milliseconds from MWCNTs immersed in metal precursors by flash light irradiation at room temperature and ambient conditions. The fabricated Pt-based alloy nanoparticle /MWCNT catalysts were characterized by X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, Raman spectroscopy, and scanning electron microscopy. In order to evaluate the electro-catalytic surface area and methanol oxidation of Pt and Pt-Ru alloy catalysts, Cu-stripping voltammetry, cyclic voltammetry, linear sweep voltammetry studies and electrochemical impedance spectroscopy analysis were conducted. When compared to catalysts fabricated by a conventional chemical fabrication process, a Pt50-Ru50/MWCNT catalyst fabricated directly from metal precursors by flash light irradiation exhibited superior activity and stability with regard to methanol electro-oxidation.

Flash Light-Assisted Facile and Eco-Friendly Synthesis of Platinum-Based Alloy Nanoparticle/Carbon Nano-Tube Catalysts for a Direct Methanol Fuel Cell

Defined micropatterns of platinum thin films by inductively coupled plasma etching using SF6/Ar/O2 mixture gas

The inductively coupled plasma etching of platinum with \(BCl_3 /Cl_2\)-gas chemistries was examined. Plasma characteristics were investigated with increasing \(Cl_2\) ratios using a Langmuir probe and optical emission spectroscopy. The chemical reaction during the Pt etching was also examined via the chemical binding states of the etched surface, by X-ray photoelectron spectroscopy. The relationship between plasma and etch characteristics with various \(Cl_2\) gas mixing ratios is discussed. On the basis of the relationship, the Pt etching mechanism with \(BCl_3 /Cl_2\)-gas chemistries is described.

Etch characteristics of Pt by using BCl3/Cl2-gas mixtures

Inductively coupled plasma etching of platinum with Cl 2 /O 2 /Ar gas chemistries was examined. Plasma characteristics were investigated with increasing O 2 ratios using a Langmuir probe and a quadrupole mass spectrometer. The chemical reaction during the platinum etching was also examined from the chemical binding states of the etched surface by X-ray photoelectron spectroscopy. Additional characterization employed a four-point probe, thin-film thickness measuring system, and scanning electron microscopy. The relationship between plasma characteristics and etch results with various O 2 -gas mixing ratios was also studied. It was confirmed that small additions of oxygen into the Cl 2 /Ar gas mixtures lead to high selectivity and a good sidewall profile without a fence, also referred to as a bull-ear.

Nam-Kwan Hong

Papers

Etch Characteristics of Pt Using Cl2 / Ar / O 2 Gas Mixtures

Etch characteristics of Pt by using BCl3/Cl2-gas mixtures