Threshold voltage (Vth) behaviour of nitride read only memories (NROM) was studied after irradiation with photons (γ- and X-rays), light and heavy ions. Both programmed and non-programmed single cells were investigated. The data suggest that two main physical phenomena are contributing to Vth variation and that the Vth loss and the variability can be modelled by a Weibull statistics with a shape parameter k~2.2 regardless of the irradiation species and total dose. The same peculiarities were found in large memory arrays confirming the results from single cells studies but with significantly larger statistics. Hence, once the irradiation dose is known, the Vth loss distribution can be obtained, thus providing a predictive model of the radiation tolerance of NROM memory arrays.
Threshold Voltage Variability of NROM memories after exposure to ionizing radiation
PACE, Calogero;
2012-01-01
Abstract
Threshold voltage (Vth) behaviour of nitride read only memories (NROM) was studied after irradiation with photons (γ- and X-rays), light and heavy ions. Both programmed and non-programmed single cells were investigated. The data suggest that two main physical phenomena are contributing to Vth variation and that the Vth loss and the variability can be modelled by a Weibull statistics with a shape parameter k~2.2 regardless of the irradiation species and total dose. The same peculiarities were found in large memory arrays confirming the results from single cells studies but with significantly larger statistics. Hence, once the irradiation dose is known, the Vth loss distribution can be obtained, thus providing a predictive model of the radiation tolerance of NROM memory arrays.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
