THE INFLUENCE OF ION-BOMBARDMENT ON REACTIONS BETWEEN TI AND GASEOUS N-2

Simultaneous Auger electron spectroscopy and ion bombardment were used to study the influence of ion bombardment on the amount of nitrogen accumulated on a Ti surface in a low-pressure nitrogen atmosphere. The nitrogen level was measured as a function of time, ion flux, nitrogen partial pressure, and Ti temperature both directly before and during bombardment with 150 keV Ti+ions. As a result of the ion bombardment, the steady-state nitrogen level increased (and in some cases decreased) by an amount determined by the balance between the ion flux and the flux of nitrogen gas. The experimental results were interpreted in terms of a multiple-step process involving ion beam induced dissociative chemisorption of physisorbed molecular nitrogen. The time dependence of the nitrogen concentration at the Ti surface was modeled with a pair of differential equations that described the time rate of change of the physisorbed and chemisorbed contributions to the surface nitrogen in terms of both ion beam induced and thermally activated processes. These equations were solved numerically and the solutions agreed with the experimental behavior. In addition, the results of this study were used to explain observed variations in properties of thin film TiN grown by ion-assisted reactive deposition. © 1990, American Vacuum Society. All rights reserved.