Technique method of manufacturing bottom thick grate oxide layer groove metal oxide semiconductor (MOS)

Abstract

The invention discloses a technique method of manufacturing a bottom thick grate oxide layer groove metal oxide semiconductor (MOS). The technique method of manufacturing the bottom thick grate oxide layer groove MOS comprises the following steps. The first step is that an epitaxial layer grows on a heavily-doped silicon substrate, and a first lightly-doped epitaxial layer is formed; the second step is that silicon dioxide grows on the first lightly-doped epitaxial layer; the third step is that a photoresist pattern is formed; the fourth step that the silicon dioxide which is unblocked by photoresist is etched cleanly, so that the first lightly-doped epitaxial layer except the photoresist is exposed, and then the photoresist is eliminated; the fifth step is that a second epitaxial layer grows selectively; the sixth step is the silicon dioxide is etched backward to required thickness through wet process or dry process etching technology, and a groove and a thick grate oxide layer at the bottom of the groove are formed. According to the technique method of manufacturing the bottom thick grate oxide layer groove MOS, selectively epitaxial growth is adopted to form the groove, the oxide layer inside the groove is etched backward to the required thickness so as to serve as the thick grate oxide layer at the bottom of the groove. According to the technique method of manufacturing the bottom thick grate oxide layer groove MOS, the structure of the bottom thick grate oxide layer groove MOS is enabled to be easily formed and controlled.

Description

technical field [0001] The invention relates to a manufacturing method of a semiconductor device, in particular to a process method for manufacturing trench MOS with a thick gate oxide layer at the bottom. Background technique [0002] The bottom thick gate oxide layer (500-10000 angstroms thick) MOS (metal oxide semiconductor) can greatly reduce the capacitance between the gate and drain of the device. Existing processes form trenches by etching, but this method makes formation of a thick bottom gate oxide difficult. Moreover, the existing process generally only has one layer of epitaxy on heavy doping. When two layers of epitaxy are required, the relative position control of the epitaxy and the trench in the prior art process is not accurate enough, so that the optimization of epitaxy doping and device Performance work is more difficult. Contents of the invention [0003] The technical problem to be solved by the present invention is to provide a process method for mak...

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Problems solved by technology

Existing processes form trenches by etching, but this method makes formation of bottom thick gate oxide difficult

Moreover, the existing process generally only has one layer of epitaxy on heavy doping. When two layers of epitaxy are required, the relative position control of the epitaxy and the trench in the prior art process is not accurate enough, so that the optimization of epitaxy doping and device Performance work is more difficult

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