IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Thin Films Thursday Sessions
       Session TF-ThA

Paper TF-ThA3
Ionization of Sputtered Titanium Atoms in Radio Frequency Magnetron Sputtering

Thursday, November 1, 2001, 2:40 pm, Room 123

Session: Emerging Thin Film Techniques
Presenter: K. Okimura, Tokai University, Japan
Authors: K. Okimura, Tokai University, Japan
T. Nakamura, Tokai University, Japan
Correspondent: Click to Email
Recently, the ionization of the sputtered flux has received much attention for several aspects such as, assisting effect of low temperature crystallization, filling characteristics to high aspect ratio seed layer and damage in integrated circuits. We have investigated sputtered titanium(Ti) atom densities for both Ar discharge and Ar-O@sub 2@ reactive discharge by means of atomic absorption method.@footnote 1@ As for the ionization of sputtered atom, quantitative measurement is lacking for understanding ion flux incident to substrate. In this study, optical emission spectroscopy for Ti ions were performed using 250 mm monochromater in planar rf magnetron sputtering apparatus with 100 mm diameter titanium target and 35 mm electrodes spacing. Atomic absorption method using a hollow cathode lamp was also applied in order to evaluate concentration of Ti ions. A series of optical emission originated from Ti ion, 336.1 nm, 337.3 nm and 338.4 nm, were observed in a spectrum at argon pressure of 3.5 Pa and radio frequency power of 200 W. We discussed the ionization of sputtered atoms from relative intensities of ionic optical emission to atomic emission in measured spectra. Radial(r) and axial(z) profiles of optical emission intensity of Ti ions at 336.1 nm for different discharge conditions such as rf power, Ar pressure, were presented. At axial directions, z=15 mm, 21 mm, 27 mm, maximum emission of Ti ion located at radial position around r=35 mm where was slightly outward position compared to the position with maximum strength of transverse magnetic field. Absorption measurement of 336.1 nm line showed absorption intensity around 10@super -2@ indicating ionization degree less than several percent for sputtered Ti atom density. Plasma parameters and mass-resolved analyses of incident ions were served for discussion on mechanism of ionization and ion flux incident to substrate. @FootnoteText@ @super 1@T.Nakamura and K.Okimura : to be appeared in JVST-A.