METHOD FOR SYNTHESIS OF HAFNIUM NITRATE FOR HFO2 THIN FILM DEPOSITION VIA ALCVD PROCESS

摘要

PURPOSE: Provided is a method for preparing a hafnium nitrate thin film for use in ALCVD for generating hafnium oxide by utilizing standard IC industrial chemistry and storage facilities. CONSTITUTION: The method comprises the steps of: placing phosphorus pentoxide in a first vessel(12); connecting the first vessel(12) to a second vessel(20) containing hafnium tetrachloride; cooling the second vessel(20) with liquid nitrogen; dropping fuming nitric acid into the first vessel(12) to generate N2O5 gas; introducing the N2O5 gas into the second vessel(20); heating the first vessel(12) until the reaction of generating N2O5 is substantially complete; disconnecting the two vessels; removing the second vessel(20) from the liquid nitrogen bath(26); heating the second vessel(20); refluxing the contents of the second vessel(20); drying the compound in the second vessel(20) by dynamic pumping; and purifying the compound in the second vessel(20) by sublimation to produce Hf(NO3)4.