Manufacturing process for charge trapping device

Abstract

The invention discloses a method for manufacturing charge trapping devices, which includes steps of depositing a sacrificial silicon nitride layer on the upper end face of a semiconductor substrate, shaping an oxide film layer for forming sidewalls, forming the sidewalls on two sides of the sacrificial silicon nitride layer, removing the sacrificial silicon nitride layer and retaining the sidewalls on two sides thereof, utilizing the sidewalls as dielectric isolating layers for manufacturing a gate tube and a memory tube, shaping ONO films on the surfaces of the silicon substrate and the dielectric isolating layers, etching off the ONO films formed on the end face of the silicon substrate, wherein the ONO films are used to form a position for a gate tube gate oxide layer, further depositing a gate oxide layer of the gate tube, shaping a polysilicon layer, and etching the polysilicon layer to form the gate tube and the memory tube. The method can effectively reduce the distance betweenthe gate tube and the memory tube, easily controls the dimension of the polysilicon gate and is favorable for increasing integration level of flash memories.

Description

technical field [0001] The invention relates to a manufacturing process method of a semiconductor integrated circuit, in particular to a manufacturing process method of a charge trapping device used in an EEPROM (Electrically Erasable Programmable Read-Only Memory). Background technique [0002] With the development of semiconductor integrated circuit technology, how to reduce the area used by devices and improve the integration of circuits is the goal of continuous exploration and pursuit in the industry. Charge trapping devices are very effective in reducing the size of flash memory and EEPROM memory cells, and are also a technical means often used by non-volatile memory circuit design engineers. The charge trapping device is the so-called SONOS (polysilicon-oxide-nitride-oxide-silicon polysilicon-silicon dioxide-silicon nitride-silicon dioxide-silicon) structure, and the device has a very simple manufacturing process. [0003] The method often used in the existing manufa...

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Problems solved by technology

[0003] The method often used in the existing manufacturing process is to form the selection tube and the storage tube by one-step etching after the growth of polysilicon, but it is difficult to form a very small distance between the selection tube and the storage tube. , so the distance between the selection tube and the storage tube is relatively large in the usual process, which makes the size of the entire storage unit difficult to shrink (see Figure 10 )

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