Voltage scaling of ferroelectric thin films deposited by CVD

For many applications of ferroelectric ICs it is desirable to operate ferro electric memory at the lowest possible power and voltage. One way to reduce the operating voltage is to reduce film thickness. We report on the electr ical properties of MOCVD deposited PZT 40/60 and 20/80 films as a function of film thickness. As the thickness is reduced, switched polarization at sa turation (P*-P-boolean AND) is reduced, but the coercive E-field is not sub stantially changed. Films also have imprint and fatigue behavior that is in dependent of film thickness when operated at constant electric field. For f ilms below 60nm the leakage current rises rapidly; this is likely due to th e effects of film roughness. For 65nm films of the PZT 20/80 material, we o bserved well formed hysteresis loops and P-sw > 55 mu C/cm(2) at 1.2V; pola rization was greater than 90% saturated at that voltage.