A semi-floating gate storage device with u-shaped trench and its manufacturing method

Abstract

The invention discloses a semi-floating gate storage device with a U-shaped trench and a manufacturing method thereof. After the threshold voltage Vt implantation of the U-shaped trench is completed, a large-angle implantation step is added, so that the The sidewall of the U-shaped trench forms a heavily doped region, which not only increases the threshold voltage of the parasitic MOSFET on the sidewall of the U-shaped trench, reduces the leakage and potential fluctuation of the half-floating gate, but also further enhances the charging current of the TFET to the half-floating gate. and shorten the writing time; the invention can increase the access speed, prolong the charge storage time of the half-floating gate, and at the same time, the performance parameter fluctuation between devices is small, and is suitable for large-scale integration.

Description

technical field [0001] The present invention relates to the technical field of semiconductor storage devices, and more particularly, to a semi-floating gate storage device with a U-shaped trench and a manufacturing method thereof. Background technique [0002] At present, semiconductor memory devices have been widely used in various electronic products. Among them, different application fields have different requirements on the structure, performance and density of semiconductor memory devices. For example, static random access memory (SRAM) has high random access speed and low integration density, while standard dynamic random access memory (DRAM) has high density and medium random access speed. [0003] As a new type of memory device, the semi-floating gate device can be applied to different integrated circuits. Semi-floating gate memory can replace a part of static random access memory (SRAM). The SRAM unit area composed of semi-floating gate transistors is smaller, and...

AI Technical Summary

Problems solved by technology

However, in this type of semi-floating gate memory device structure, there is a parasitic MOSFET in the vertical direction of the channel on the side wall of the U-shaped trench; the MOSFET has a small threshold voltage Vt due to less channel doping and a small channel length, and has Strong short channel effect

This seriously affects the retention time of the charge in the half-floating gate, and will cause fluctuations in the potential of the half-floating gate, large fluctuations between devices, and large-scale integration.

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