Manufacturing method of memory device

Abstract

A manufacturing method of a memory device provided by the invention comprises the following steps of: providing a substrate; forming a gate insulating layer and a contact window on the substrate; forming a floating gate material layer; etching the floating gate material layer; executing an oxidation process to oxidize the part of the floating gate material layer, which is located at one side of the first drain region and exceeds the first contact window, and oxidize the part of the floating gate material layer, which is located at one side of the second drain region and exceeds the second contact window, so as to form a side wall oxide layer; and removing the side wall oxide layer and the gate insulating layer outside the coverage range of the floating gate material layer. Therefore, the part of the gate insulating layer is not reserved between the substrate and a semi-floating gate at one side, close to the drain region, of the contact window, so that when a semi-floating gate transistor works, the potential barrier of carriers entering the semi-floating gate is reduced, the risk that the carriers are captured by silicon dioxide / silicon interface defects is reduced, the speed of carriers entering the semi-floating gate and a programming speed of the semi-floating gate transistor can be increased, and the reliability of the memory device is improved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for manufacturing a storage device. Background technique [0002] Semiconductor memories are used in various electronic fields. Among them, non-volatile memory can save data for a long time in the case of power failure. Floating-gate transistors are a mainstream type of non-volatile memory. In general, a floating gate transistor has a stacked gate structure comprising a floating gate (floating gate) and a control gate (control gate) at least partially covering the floating gate, wherein the floating gate is surrounded by an insulating dielectric , by applying a high voltage to control the carriers to pass through the gate insulating layer in the way of tunneling or hot carrier injection, thereby changing the amount of stored charges in the floating gate, the threshold voltage of the transistor can be adjusted, that is, corresponding to the logic "0" and "1". H...

AI Technical Summary

Problems solved by technology

[0005] However, the programming speed of the current semi-floating gate transistors is not enough, which affects the reliability of memory devices including semi-floating gate transistors.

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