Method of reducing the occurrence of burn-in due to negative bias temperature instability

A method for alleviating burn-in effect and enabling performing a start-up process in respect of a device comprising a plurality of challengeable memory elements, wherein the memory elements are able to, upon start-up, generate a response pattern of start- up values useful for identification as the response pattern depends on physical characteristics of the memory elements, the method comprising the step of, after start-up of the memory elements, writing a data pattern to the memory elements which is inverse to a response pattern that was previously read from the same memory elements. Thus, degradation of the PMOS transistors due to NBTI can be alleviated.