Guanidinato-based precursors for MOCVD of metal nitrides (M xN: M = Ta,W)

Abstract

Refractory metal nitrides such as TaN and W x N are interesting candidates as novel gate electrodes in CMOS technology. MOCVD and, in particular, ALD are desirable deposition processes and the development of new complexes and the precursor chemistry plays a vital role. We are interested in fine-tuning the properties of key precursors by ligand variation and introducing the chelating all-nitrogen coordinating groups such as guanidinato and β-diketiminato ligands. Guanidinato ligand-based complexes of groups V and VI, especially Ta, and W are interesting precursors for MOCVD and ALD of respective metal nitride thin film growth. As a representative example, evaluation of Ta- and W-based guanidinato complexes as MOCVD precursors and thermal analysis of the new complexes by TG–DTA analysis will be presented. The MOCVD of TaN, W x N thin film growth using our novel mixed ligand precursors and the film characterization by XRD, SEM, cross-sectional SEM, SNMS and conductivity measurements (four-point probe analysis) is discussed in detail. Ta-guanidinato complexes were also used as a single source precursor for MOCVD of TaN. Nearly stoichiometric cubic TaN films with very less carbon content were obtained with good conductivity values.