Transition metal nitride thin films are important in many areas of microelectronics. The most important challenge today is the adoption of copper interconnects in the integrated circuits, which requires the use of a diffusion barrier because copper is known to diffuse through silicon dioxide-based dielectrics. The most promising diffusion barrier materials are transition metals, metal nitrides, metal silicides, and metal-silicon-nitrides. Because for a long time the semiconductor industry has used Ta-, Ti-, and W-based materials, these transition metals and their compounds are also the most studied materials for barrier applications. The deposition of nitride thin films has mainly been performed with various physical vapor deposition (PVD) and chemical vapor deposition (CVD) techniques. These, however, suffer from various difficulties. Films can be grown at quite low temperatures using the PVD techniques, but their step coverage is poor and therefore their use in manufacturing the future generation integrated circuits is limited. More conformal films are achieved by using the CVD techniques, but unfortunately the needed growth temperatures are often too high. In addition good conformality and good electric properties are often difficult to achieve at the same time. In the traditional CVD deposition processes, titanium nitride (TiN) films are deposited from TiCl 4 , H 2 , and N 2 at temperatures above 750ЊC. 2 If NH 3 is used instead of H 2 and N 2 , high conductivity films with low chlorine contamination levels can usually be deposited at temperatures exceeding 550ЊC. 3-9 Nowadays alternative precursors, particularly alkyl amides, 10-15 additional energy sources, 16 and post-or intermediate deposition plasma treatments Atomic layer deposition (ALD), also known as atomic layer epitaxy (ALE), TiN, 25-28 TaN, 27,29 NbN, 27,30 MoN, 27 WN, 31 and Ti-Si-N 32 films have already been deposited by the ALD method. Except for Ti-Si-N and one TiN process, where alkyl amines were used, 28 halides have been used as the metal source and ammonia as the nitrogen source. An intermediate zinc pulse between the chloride and ammonia pulses has been proven to be effective in improving the electrical properties of the TiN, The oxidation number of the metal in the conventional precursors is higher than in the desired nitride and therefore reduction is required. At the present time ammonia has been the most often used and studied nitrogen source in ALD. However, NH 3 is quite stable and not a very effective reducing agent and therefore, alternative more reactive nitrogen sources should be sought. One of the possible choices is hydrazine, N 2 H 4 , which is more reactive than NH 3 . The radical formation enthalpie
