Adsorption and reaction of NH3 on Ti/Si(100)

The nitridation of ultra-thin Ti films on Si(1 0 0) have been studied using X-ray photoelectron spectroscopy (XPS) in a temperature range of 120-1000 K. Upon ammonia exposure to the multilayer Ti thin films at 120 K, three N is peaks at 397.8-398.1. 400.5-400.8 and 402.2-402.6 eV were observed, attr ibutable to NHx (x = 1 or 2). molecular NH3 and NH4sigma+, respectively. An nealing of the NH3 saturated Ti/Si(1 0 0) surfaces results in the conversio n of the NHx species, This species undergo two different pathways between 3 00 and 800 K, i.e. further dissociation to N(a) and H(a), and recombing wit h H(a) to form NH3(g). The atomic N reacts with Ti to yield a stable TiN fi lm that retards significantly the interdiffusion at the Ti/Si interface. (C ) 2001 Published by Elsevier Science B.V.