Characterization of tantalum pentoxide dielectric films grown by low-pressure and plasma-enhanced chemical vapor deposition

The material properties as well as the electrical behavior of tantalum pentoxide (Ta2O5) thin films prepared by low-pressure chemical vapor deposition (LPCVD) and plasma-enhanced chemical vapor deposition (PECVD), in the same reactor, were studied. Ta2O5 films were grown on Si and Pt substrates by reacting pentaethoxy tantalum [Ta(OC2H5)(5)] with oxygen and were annealed in an oxygen furnace at 700 degreesC or oxygen plasma at 350 degreesC. Scanning electron microscopy (SEM), secondary ion mass spectroscopy (SIMS), Auger electron spectroscopy (AES). capacitance-voltage (C-V) and current-voltage (I-V) measurements were employed to characterize the Ta2O5 films before and after annealing, Compared to the LPCVD Ta2O5 film, the PECVD Ta2O5 film deposited at an rf power of 80 W exhibited a denser structure and better dielectric characteristics. Oxygen plasma annealing further densified the Ta2O5 films and improved their electrical performance on either Si or Pt substrate, without deteriorating the substrate materials.