SONOS (silicon oxide nitride oxide semiconductor) nonvolatile memory and manufacturing method thereof

Abstract

The invention discloses a SONOS nonvolatile memory. A grid of a SONOS memory transistor and a grid of a selective transistor of a unit structure of the SONOS nonvolatile memory are of a two-layer isolated overlapped structure; the first side face of the selective transistor is provided with a first insulating medium side wall; a tunnel injection region and an ONO layer of the SONOS memory transistor are aligned with the first insulating medium side wall; the whole unit structure only comprises two source and drain regions; no source and drain regions exist between the grid of the SONOS memory transistor and the selective transistor. The invention also discloses a method for manufacturing the SONOS nonvolatile memory. A source and drain region between grids of the two transistors is omitted directly, the area of the memory unit can be greatly reduced, and an additional etching step is not added.

Description

technical field [0001] The invention relates to a semiconductor integrated circuit manufacturing process method, in particular to one. Background technique [0002] SONOS non-volatile memory is widely used in advanced flash memory and electrically erasable memory products. At present, the commonly used memory cell structure consists of a complete SONOS memory transistor and a complete select transistor to form a 2-transistor structure (2T structure), each transistor has a complete source, drain and gate, and the two transistors share a layer polysilicon. Such as figure 1 Shown is the cell structure diagram of the existing SONOS non-volatile memory; the cell structure of the existing SONOS non-volatile memory includes a SONOS memory transistor and a selection transistor, the cell structure is formed in the P well 102, the P Well 102 is formed in deep N-well 101 of silicon substrate 100 . [0003] The gate structure of the SONOS memory transistor includes an ONO layer 104 ...

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