Hood curtain type read-only storage capable of storing multi order information

Abstract

A mask ROM able to store multiple bit information is composed of a substrate, the first deeper channel and second shallow channel in the substrate, a conformal dielectric layer on the side walls and bottoms of both channels, a conducting layer filled in both channels, a first doped region under the first channel, a second doped region under the second channel, and a third doped region in the surface of substrate between two channels.

Description

(1) Technical field [0001] The present invention relates to a memory element, in particular to a masked read-only memory for storing multi-bit information. (2) Background technology [0002] There are many known types of ROMs in use today; one such type is the flat ROM. In order to meet the requirement of better memory cell efficiency, the pitch and bank height of memory cells become important design considerations. When the design size of the memory cell gradually shrinks, the size of the contact window and the metal pitch also become one of the limiting factors; It will make it difficult to reduce the layout area. [0003] Generally speaking, ROM is used to store data information in a permanent, non-volatile memory form. Semiconductor read-only memory is mostly used in digital electronic devices, such as computers, business machines and game machines, etc., and data information can be permanently stored in this device. Such permanent data information includes micro-pro...

AI Technical Summary

Problems solved by technology

However, the traditional mask-type ROM has a small process space, and the channel length is the same. If different voltages are applied, there are only two types of "0" and "1", and the space for storing data is small.

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