Patent ID: 7111210

Claim:
An accelerated test method for evaluating, under accelerated conditions (a temperature T 2 and a voltage V 2 ), an endurance characteristic of a ferroelectric memory device comprising a capacitor element having a ferroelectric film under actual operating conditions (a temperature T 1 and a voltage V 1 ), the method comprising the step of: deriving an acceleration factor (K) required to evaluate the endurance characteristic by using a following expression (1): log K=A (1/ V 1 −1 /V 2 )+ B (1/ V 1 T 1 −1 /V 2 T 2 ) (where each of A and B is a constant), the method further comprising the sub-steps: determining the number (Lc) of occurrences of polarization inversion when a remanence of the ferroelectric film reaches a specified decrease rate at each of a plurality of polarization inversion voltages (V) at a plurality of temperatures; determining a constant (α) at a specified temperature (T) by using a following expression (2): log Lc=C+α/V (where each of C and α is a constant) (2); and determining the constants A and B by using a following expression (3): α= A+B/T (3).