Conformal growth and characterization of hafnium silicate thin film by MOCVD using HTB (hafnium tertra-tert-butoxide) and TDEAS (tetrakis-diethylamino silane)

Abstract

Hafnium silicate (HfSixOy) films were deposited by metal-organic chemical vapor deposition (MOCVD) using hafnium tetra-tert-butoxide [HTB, Hf(OC(CH3)(3))(4)] and tetrakis-diethylamino silane [TDEAS, Si(N(C2H5)(2))(4)]. The grown Hf-silicate films showed Hf-rich composition and impurity concentrations less than 1 atomic % ( below detection limits). Uniformly deposited films with good step-coverage were obtained on hole-patterned SiO2 substrates. Hafnium silicate films had stable amorphous crystalline structure up to 800 degrees C annealing and above 900 degrees C, a tetragonal HfO2 crystal phase was observed. Dielectric constant (k) of the Hf-silicate films was about 15 and flat band voltage (V-fb) and hysteresis were very low.