Preparation method of Splitt-Gate MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) device

Abstract

The invention discloses a preparation method of a Spit-Gate MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) device, and relates to the technical field of semiconductor power devices. The method is used for solving the problem that in the prior art, a forming process Splitt-Gate MOSFET device manufacturing process has contradiction between cost saving and good device performance. The preparation method comprises the following steps: sequentially forming a liner Oxide layer and a source poly layer in a first groove and a second groove; the source poly layer in the second groove is etched in sequence through an etching method, the second oxide layer included in the hard mask plate is removed, and the liner oxide layer in the second groove is etched; etching the source poly layer in the first groove and the source poly layer in the second groove through an etching method; a gate oxide layer and a gate poly layer are sequentially formed on the portion, in the second groove, of the source poly layer, and the gate oxide layer and the gate poly layer are sequentially formed on the portion, in the second groove, of the source poly layer; forming a second conductive type body region and a first conductive type source region through two times of ion implantation; and preparing a contact hole on the isolation oxide layer.

Description

technical field [0001] The invention relates to the technical field of semiconductor power devices, in particular to a method for preparing a Split-Gate MOSFET device. Background technique [0002] With the continuous maturity of process technology, Split-Gate MOSFET devices are gradually replacing Single Trench MOSFET devices in many fields. However, due to the difficulty of the process, the production cost is still higher than that of Singlerench devices, which restricts split-gate devices. growth trend. However, the existing one-step forming process Split-GateMOSFET device manufacturing process has the following contradictions between cost saving and good device performance. First, if a layer of photomask is reduced in order to save costs, it will form gate poly residues on the top of the Source poly around the device. As a result, the device has a risk of excessively large gate leakage, and if the risk is to be improved, the cost of the device will inevitably be increas...

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Problems solved by technology

[0002] With the continuous maturity of process technology, Split-Gate MOSFET devices are gradually replacing Single Trench MOSFET devices in many fields. The production cost is still higher than that of Singlerench devices, thus restricting the growth trend of split-gate devices

However, the existing one-step forming process Split-GateMOSFET device manufacturing process has the following contradictions between cost saving and good device performance. First, if a layer of photomask is reduced in order to save costs, it will form gate poly residues on the top of the Source poly around the device. As a result, the device has a risk of excessive gate leakage, and if this risk is to be improved, it will inevitably increase the cost of the device

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