Modification of Structure and Properties in Ti Films Deposited by Rf-plasma-assisted Dc and Pulsed Dc Sputtering

Abstract

  Structure and properties of Ti films deposited by direct current (dc) magnetron sputtering and pulsed dc magnetron sputtering with or without inductively coupled rf plasma assist have been investigated for various discharge pressures. With inductively coupled rf plasma assist, (1) resistivity of Ti films decreased, (2) surface became smooth, and (3) light reflectance increased, in particular, for a discharge pressure of 2.0 Pa, compared to those of Ti films deposited by conventional dc sputtering. By cross-sectional SEM investigation, it was found that Ti film deposited by pulsed dc sputtering with rf-plasma-assist at a pressure of 2.0 Pa became denser than that of Ti film deposited by dc sputtering without rf-plasma-assist at a pressure of 2.0 Pa. It is presumed that a Ti film with a fine columnar structure results from the enhancement in the energy transferred to the surface of a growing film due to the increase in ion fraction and ion energy in the combination of pulsed dc discharge and inductively coupled rf discharge.