Method of forming ferroelectric capacitor in semiconductor device

摘要

A semiconductor fabrication technique for forming a ferroelectric capacitor, in which the thermal burden is reduced by using an SBT-based ferroelectric thin film such as SrxBiyTa2O9 ("SBT') or SrxBiy(TaiNbj)2O9 ("SBT(N)') as the dielectric medium. The method includes the following steps. A strontium-bismuth-tantalum oxide film is formed on a semiconductor substrate, with a conductive film for a lower electrode having been formed on the semiconductor substrate (first step). An NH3 gas is flowed at a stabilizing step of a rapid thermal annealing so as to reduce organic materials bonded with metal elements of the strontium-bismuth-tantalum oxide film (second step). An oxide gas is flowed at a temperature of 450~650° C. at an annealing step of the rapid thermal annealing so as to induce a perovskite nuclear formation in the strontium-bismuth-tantalum oxide film (third step). A furnace annealing is then carried out so as to induce a grain growth in the strontium-bismuth-tantalum oxide film (fourth step).