Thermodynamics and growth kinetical consideration of metal-nitride formation by nitrogen implantation

Based on summarizing the experimental results so far obtained, an attempt is made to answer why and how a specific nitride may or may not be obtained by direct nitrogen implantation. Attentions were paid in particular to the Ti-N and noble metal-N systems. For the Ti-N system a fine experiment at very high implantation dose was conducted. The phases produced in implanted samples were identified by means of transmission electron microscopy, electron spectroscopy for chemical analysis, and X-ray diffraction analysis. The mechanism of metal nitride formation by nitrogen implantation can be explained considering both thermodynamics and growth kinetics. The structural compatibility plays an important role in the process of nitride formation. The noble-metal nitrides, e.g. AgN3 and CuN3, in spite of their positive value of the heat of formation, could be formed by direct nitrogen ion implantation. The nitrides so far obtained are classified into two categories. One is easily obtained, while the other is hard to form or even not accessible by conventional methods. 49 refs