One-time programmable memory and manufacturing method

Abstract

The invention discloses a one-time programmable memory and a manufacturing method. The one-time programmable memory comprises a plurality of memory cells, each memory cell comprises a control MOS (metal oxide semiconductor) tube and a read MOS tube in serial connection, and each read MOS tube comprises a floating gate in an inverted trapezoidal structure with the big end up. The read MOS tube manufacturing method includes steps: providing a substrate; sequentially forming a dielectric layer and a gate layer on the substrate; imaging the gate layer by etching with undercutting to form a gate in an inverted trapezoidal shape with the big end up; imaging the dielectric layer by etching to form a gate dielectric layer; doping the substrate by using the gate and the gate dielectric layer for masking to form a doped area; and forming a side wall enclosing the gate and the gate dielectric layer, wherein the side wall, the gate and the gate dielectric layer form a gate structure. By means of the one-time programmable memory and the manufacturing method, data retention of the one-time programmable memory can be improved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a one-time programmable memory and a manufacturing method. Background technique [0002] One time programmable memory (One Time Programable, OTP) is one of common memories, and after information is written in the OTP, the information cannot be changed again. Because the manufacturing process of OTP is relatively simple, the cost is low, and OTP also has certain flexibility at the same time, so the application of OTP is relatively extensive. [0003] Based on different OTP structures, the OTP is divided into coupling capacitor type, series transistor type, dielectric breakdown type and the like. [0004] refer to figure 1 , shows a schematic structural diagram of an embodiment of the prior art OTP. The OTP is an example of a series transistor type OTP. The OTP includes a plurality of storage units, and each storage unit includes two NMOS transistors connected in series. ...

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Problems solved by technology

However, the distance d between the plug 12 and the floating gate 11 is getting smaller and smaller, and the reduction of the distance d will cause the charge in the floating gate 11 to be lost through the plug 12, thereby affecting the performance of the floating gate 11. Threshold voltage, which in turn causes a decline in OTP's data retention (Data Retention)

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