Increasing radiation resistance of memory devices based on amorphous semiconductors

Abstract

A memory cell structure is proposed that uses a Schottky barrier thin film transistor based on an amorphous semiconductor as a junction element, and a chalcogenide glassy semiconductor film as a switching element. A physical storage cell model has been developed. The dependence of the transistor and memory cell parameters on the dose of neutron flux and γ-quanta was investigated. It is shown that when the dose of neutron irradiation is changed, the steepness of the drain-gate characteristic (DGC) decreases by 10% at a dose of the order of 1015 n/s, and at the same time, the transfer coefficient of the bipolar n-p-n transistor decreases by 20% at doses of 1013 n/s, indicating a significant increase in the radiation resistance of the proposed memory cell. In the case of irradiation with γ-quanta in the range up to 2.6 MRad, the steepness of the DGC of the proposed structure changes by only 10%. When used as an isolation element, a field-effect transistor with an insulated gate, the slope of the DGC is reduced by 50%. It is shown that the current of recording information of the proposed structure when changing the dose of γ - quantum flux to 2.6 MRad changes by about 10%, and at the same time, in the case of using a field-effect transistor with an isolated cover, the information recording current changes by 50%. The study of the dependence of the gate current on the dose of the γ-quanta is shown. When the radiation dose changes 0 to 2.6 MRad, the gate current changes only by 10%, which indicates the high resistance of the proposed structure to the action of permeable radiation. Also, studies of the dependence of the conductivity of single-crystal semiconductors on a radiation dose ɣ by quanta and neutron flux show that a significant increase in the specific resistivity of amorphous semiconductors occurs at doses 2–3 orders of magnitude larger than in the case of single-crystal n-type conductivity semiconductors.