Effects of different pretreatments on the surface structure of silicon and the adhesion of metal films

Interface structures and adhesion to silicon after different surface pretreatments have been investigated for Ni(500–1000 nm)/Ti(250 nm) films prepared in a dc planar magnetron sputtering apparatus. In order to obtain high adhesion, a chemical pretreatment (with buffered HF) has been found to be favorable in comparison with a conventional Ar ion bombardment pretreatment (with cathodic voltage: 400 V). High resolution transmission electron microscopy (HRTEM) showed that there were two layers between Ti and Si in the case of Ar ion bombardment pretreatment. Energy dispersive x‐ray spectroscopy (EDS) and electron diffraction (ED) showed that they were amorphous Ti–Si alloy and amorphous Si containing Ar. Moreover, a peeling pattern, after the test with adhesive tape, could be found at the boundary between the amorphous Ti–Si alloy layer and the amorphous Si layer containing Ar by using x‐ray photoelectron spectroscopy (XPS). In the case of chemical pretreatment, only an amorphous Ti–Si alloy layer was observ...