EFFECTS OF ELECTRON-HOLE GENERATION, TRANSPORT AND TRAPPING IN MOSFETS DUE TO GAMMA-RAY EXPOSURE

Ionizing radiation has been found to seriously change the electrical p roperties of solid-state devices, leading to possible systems failure. The ionizing radiation effects on different n- and p-channel MOSFETs have been studied, where the failure mechanism is found to be mainly d ue to changes in oxide properties and surface effects which occur in t he gate oxide and, or, field/oxide regions. As a result, the threshold voltage of the n-channel transistor was shifted from 1.10 to 2.65 V, while the channel mobility for both the n- and p-channel transistors d ecreases from 4500 and 3100 to 2000 and 1000 m(2)/Vs, respectively. Be sides, the transconductance drops from 610, 500 and 380 down to 51, 35 and 150 mS for the MFE 201. (n-channel), 3N128 (n-channel) and 3N163 (p-channel) transistors, respectively. Also, the net effect of charge trapping can also be seen as a random, stochastical process represente d by global noise parameters. Finally, the gain and noise parameters h ave been investigated as a function of gamma-dose.