DEIS - University of Bologna

MicroLAB Research Topics

Non-volatile memories physics and reliability characterization

The activity on non-volatile memories is focused to the physical characterization of single devices as well on the study of the reliability of single celle as well as full arrays. Single cells are analized in order to evaluate the electrical characteristics (as capacitive couplings, injection efficiency etc.) of cells realized useing different technologies. Among these EEPROMS, EPROM and Flash EPROM have been studied and models for accurate simulation of the programming characteristics have been tuned. To this purpose, in particular, an improved SPICE model taking into account quantum phenomena taking place into the semiconductor has been presented and validated by means of measurements performed on EEPROM cells. Cells reliability study covers both endurance and data retention. From the memory devices point of view, Flash EPROM arrays are studied to investigate both topological dependence of the threshold voltage distribution and erratic bits. Finally the activity covers application of non-volatile memory cells as part of an electrically trimmable analog circuit.