PIP (poly-insulator-poly) capacitor of split gate type flash memory and manufacturing method of PIP capacitor

Abstract

The invention provides a PIP (poly-insulator-poly) capacitor of a split gate type flash memory and a manufacturing method of the PIP capacitor. The manufacturing method includes that: a substrate comprises a periphery area and a core area, a memory structure of the memory is formed on the core area, a peripheral circuit is formed on the periphery area; an isolation structure is formed in a semiconductor substrate of the periphery area; at least one first groove is formed in the isolation structure; a first polycrystalline silicon layer is formed on the surface of the isolation structure, the first polycrystalline silicon layer in the first grooves surrounds to form second grooves; a medium layer is formed on the first polycrystalline silicon layer, the medium layer in the second grooves surrounds to form third grooves; and a second polycrystalline silicon layer is formed on the surface of the medium layer. The invention further provides the PIP capacitor of the split gate type flash memory. By the aid of the manufacturing method, effective contact areas between an upper electrode and an insulating layer and between the insulating layer and a lower electrode of the PIP capacitor of the split gate type flash memory are enlarged, and PIP capacitor occupied area of a chip is decreased.

Description

technical field [0001] The invention relates to the field of semiconductors, in particular to a PIP capacitor and a preparation method of a split-gate flash memory. Background technique [0002] In the current semiconductor industry, capacitors are prepared by various methods, including MOS capacitors, PIP (Poly-Insulator-Poly) capacitors, MIM (Metal-Insulator-Metal) capacitors, and the like. Compared with MOS capacitors, PIP capacitors have good characteristics and strong linearity, and MOS capacitors need to be grown by thermal oxidation to form an insulating layer, and the insulating layer needs to be highly doped. However, the PIP capacitor only needs CVD growth to form an insulating layer, and the preparation process is simple and the preparation efficiency is high. MIM capacitors usually use the metal inside the device as the lower electrode of the capacitor, and then deposit an insulating dielectric layer and a metal layer on the lower electrode, and then perform pho...

AI Technical Summary

Problems solved by technology

[0007] The unit capacitance value of the PIP capacitor formed by the prior art is small, so that the PIP capacitor occupies a large area of ​​the chip, which hinders the development of semiconductor devices in the direction of miniaturization

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