A study on the crystallographic orientation with residual stress and electrical property of Al films deposited by sputtering

Abstract

Al metallization on the Si substrate was carried out by rf magnetron sputtering as a function of working pressure and the negative bias voltage. The residual stress, the resistivity, and the crystallographic orientation were investigated. The residual stress of Al thin films fabricated in the range of 1 to 40 mTorr showed tensile stress from similar to 125 MPa to 0. Applying negative bias of - 200 V to the substrate at a fixed working pressure of 1 mTorr, the residual stress changed to the compressive stress of similar to 70 MPa. The crystallographic orientation showed a random orientation at zero stress state. As the compressive stress increased, it changed to (200) preferred orientation. This relationship was explained by the strain energy. But it changed to (111) preferred orientation as the tensile stress increased. Resistivity in the Al thin films increased as the compressive stress increased. Ar entrapment by the bombardment effect was responsible for this relationship. (C) 1998 Elsevier Science S.A. All rights reserved.