Effect of Annealing on the Structural, Chemical and Electrical Characteristics of the HfO2 Thin Films

ABSTRACT.  

Senol KAYA¹, Ramazan LOK¹, Aliekber AKTAG¹, H. KARACALI¹,  Ilker YILDIZ², Ercan YILMAZ¹

¹Abant Izzet Baysal University Center for Nuclear Radiation Research and Applications, Bolu 14280, Turkey
² Central Laboratory, Middle East Technical University, Ankara 06800, Turkey

senolkaya52@gmail.com

Nowadays researchers have been considered to exploring the new high-k materials to be used in state of art CMOS technology to replace conversional SiO₂ dielectrics. Various high-k dielectrics materials HfO₂ have been considered, but the HfO₂ has reported as one of the most promising materials among them. In addition, crystallization and morphological variations change the electrical performance of the device. Hence we aim to study effects of annealing temperature on the Structural, chemical and electrical characteristics of the HfO₂ thin films deposited by RF sputtering. The annealing were performed at 300 °C and 550 °C in forming gas environment for 30 minutes. The structural characterizations were studied by XRD and AFM measurements while the chemical evolution and electrical characteristics were discussed by XPS and C-V measurements of the film, respectively. Results demonstrate that the film crystallinity were enhanced and surface roughness decrease with annealing. In addition, the SiO₂ interfacial layer formation was observed after annealing and the peak intensity rise with annealing temperature. The capacitances of device significantly decrease after 550 °C annealing. It may be conclude that the optimum annealing temperature is 300 °C for the HfO₂ to be used in MOS based technology.