Fabrication method of flash memory unit

Abstract

The invention relates to a fabrication method of a semiconductor device, and discloses a fabrication method of a flash memory unit. According to the fabrication method of the flash memory unit, P-type impurity injected to a logic grate of a select gate P-channel metal oxide semiconductor (PMOS) transistor region is diffused to an N-type floating gate poly-silicon layer by a subsequent high-temperature process after the logic gate of the select gate PMOS transistor region and a logic gate of a control gate PMOS transistor region are separated, so that an N-type floating gate is changed to a P-type floating gate, a select gate PMOS transistor with a surface channel having a relatively threshold value can be successfully fabricated on the flash memory unit with a size being 55 nanometers, and mass production is achieved. Moreover, by the process of growing the logic gates and the process of separating the logic gates, the floating gate doping of the control gate PMOS transistor cannot be affected as well as the surface channel, having the relatively threshold value, of the select gate PMOS transistor is formed.

Description

technical field [0001] The invention relates to a preparation method of a semiconductor device, in particular to a preparation method of a flash memory unit. Background technique [0002] Embedded 2T_pFlash Memory (Embedded 2T_pFlash Memory) is usually integrated into system-level chips in the form of IP (Intellectual Property, intellectual property rights), such as mobile phone SIM card (Subscriber Identity Module card, referred to as "SIM card") chips, smart bank card chips, MCU (Microprogrammed Control Unit, microprogram controller) chip and so on. Because of this feature, it is called "embedded" to distinguish it from products formed by Stand-alone Flash Memory. [0003] A single device unit is composed of two P-type metal oxide semiconductor (Metal Oxide Semiconductor Field, "MOS" for short) transistors (select gate transistor and control gate transistor) connected in series, so it is called 2T_pFlash. PMOS transistors are the basic components of modern VLSI. PMOS ha...

AI Technical Summary

Problems solved by technology

[0005] However, as the size of embedded 2T pMOS flash nodes becomes smaller and smaller, the existing 0.13μm process is no longer applicable

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