Patent ID: 6995069

Claim:
A method for manufacturing a semiconductor storage device having a dielectric capacitor using a dielectric film made of a dielectric material with a perovskite type crystalline structure, comprising the steps of: making a lower electrode of said dielectric capacitor; making on the lower electrode a precursor film having as its major component an amorphous phase made up of Bi, Sr, Ta, Nb, Ti and; making an upper electrode on said precursor film; etching at least the upper electrode and the precursor film to form the dielectric capacitor; and after making the upper electrode and etching, annealing the precursor film to change the fluorite phase to a crystal phase of a perovskite type crystalline structure so as to obtain the dielectric film, wherein, the atomic composition ratio of the precursor film is in the range of 0.6≦2Sr/(Ta+Nb)≦1.2, 1.7≦2Bi/(Ta+Nb)≦2.5, 0<2Ti/(Ta+Nb)≦1.0), making the precursor film on the lower electrode comprises depositing an amorphous film having the amorphous phase, depositing the amorphous film comprises the steps of: heating the lower electrode to a temperature between 400° C. and 650° C., preparing a source material gas by mixing an organic metal source material gas first with an argon carrier gas and then with an oxygen gas, introducing the source material gas to the lower electrode, and annealing the amorphous film to change the amorphous phase to a fluorite phase so as to create a fluorite film as the precursor film, and the organic metal source material gas used in depositing the amorphous film contains predetermined ratios of: at least one organic metal source material selected from a first group consisting of Bi(C 6 H 5 ) 3 , Bi(o-C 7 H 7 ) 3 , Bi(O—C 2 H 5 ) 3 , Bi(O-iC 3 H 7 ) 3 , Bi(O-tC 4 H 9 ) 3 and Bi(O-tC 5 H 11 ) 3 , at least one organic metal source material selected from a second group consisting of Sr(THD) 2 , Sr(THD) 2 tetraglyme and Sr(Me 5 C 5 ) 2 . 2THF, at least one organic metal source material selected from a third group consisting of Ti(i-OC 3 H 7 ) 4 , TiO(THD) 2 and Ti(THD) 2 (i-OC 3 H 7 ) 2 , and at least one organic metal source material selected from a fourth group consisting of Ta(i-OC 3 H 7 ) 5 , Ta(i-OC 3 H 7 ) 4 THD, Nb(i-OC 3 H 7 ) 5 and Nb(i-OC 3 H 7 ) 4 THD.