Read-only memory and its manufacture

Abstract

Abstract PURPOSE:To obtain an ROM speedily and easily, by varying the thereshold value of an MIS structure element through partial irradiation with electron beams and particle beams. CONSTITUTION:Specific transistors (TR) Q12, Q15-, etc., in MISTR groups Q11- Q14, Q21-Q24- arranged in a matrix are irradiated with electron beams having necessary energy. Some of the electron beams pass through the polycrystalline silicon of a gate part to reach a gate insulating film and silicon right under it, increasing the surface potential density. Thus, the specific TRs Q12, Q15- increase in threshold voltage, and bit outputs corresponding to those TRs Q12, Q15- have binary values different from those of other TRs. This method which eliminates the need for a photomask and photoetching allows speedy and easy manufacture of an ROM having desired contents. Further, the same result is obtained even by irradiation with particle beams.

Inventors

• 👤 Takeshi Kimura
• 👤 武司 木村

Bibliographic Details