Study on a Single NFET Degradation After Circuit Modification With FIB

The use of FIB in circuit modification can generate huge influences on MOS transistor parameters. It is necessary to investigate and understand the effects that occur after Ga irradiation to evaluate the influence on the behaviour of the modified structures. In this paper we investigate influences on the threshold voltage of an n-FET MOS transistor in a standard, state of the art 0.17 µm DRAM technology, after FIB irradiation. In particular, the effect of varying the distance (vertical and horizontal) between the location of the FIB modification and the active area as well as the possibility of recovering the induced Vth shift has been characterized.