READ-ONLY SEMICONDUCTOR MEMORY

PROBLEM TO BE SOLVED: To provide a read-only semiconductor memory whose stored data are protected against damage even if a very large amount of movable ions penetrate it through, and where no reduction in erasing speed or no increase in erasing current occurs with a decrease in write or erase effici...

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Bibliographic Details
Main Author OBATA HIROYUKI
Format Patent
LanguageEnglish
Published 03.02.1998
Edition6
Subjects
BASIC ELECTRIC ELEMENTS
ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
ELECTRICITY
INFORMATION STORAGE
PHYSICS
SEMICONDUCTOR DEVICES
STATIC STORES
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Summary:PROBLEM TO BE SOLVED: To provide a read-only semiconductor memory whose stored data are protected against damage even if a very large amount of movable ions penetrate it through, and where no reduction in erasing speed or no increase in erasing current occurs with a decrease in write or erase efficiency. SOLUTION: At least one of a drain diffusion layer 11, a source diffusion layer 12, and a control gate 14 formed of a diffusion layer formed on the surface of a semiconductor substrate 10 is led out to an electrode through the intermediary of an impurity diffusion layer 15 different from the above diffusion layer formed under an element isolating region, a protective gate 18 is formed on a floating gate 13 through the intermediary of an insulating layer 20, a part of the edge of the floating gate 13 is extended onto the above element isolating region, and the edge of the protective gate 18 confronts the impurity diffusion layer 15 different from the above diffusion layer through the intermediary of an insulating layer 17 which forms the above element isolating region.
Bibliography:Application Number: JP19960187538