AN INVESTIGATION OF ELECTRON BEAM IRRADIATION EFFECTS ON METAL-OXIDE-SEMICONDUCTOR TRANSISTORS. PART I.

A scanning electron microscope (SEM) was used to irradiate preferential areas of the gate electrode of both n- and p-channel metal-oxide-semiconductor transistors (MOST's). The SEM provided a 0.1 micron diameter beam that typically scanned a 10 x 10 micron area of the gate electrode in 8 ms. The accelerating potential of the electron beam was varied from 3 to 30 kV, and the electron beam current was varied from 1 to 300 pA. Irradiation with a positive applied gate voltage, while the source drain and substrate were grounded, produced an increase in the electric field at the oxide silicon interface. The increase in the interfacial electric field during electron bombardment was related to the formation of fixed positively charged states in the oxide.