Field-effect transistor metal-oxide-semiconductor (MOS) substrate

Abstract

The invention provides a field-effect transistor metal-oxide-semiconductor (MOS) substrate. The field-effect transistor MOS substrate comprises a P-type substrate, a first P well region and a poly-silicon layer, wherein the first P well region is arranged on the P-type substrate, the poly-silicon layer forms a structure symmetric along a first central line of a first direction, the poly-silicon layer comprises a first part, a second part and a third part relative to the first central line, the first part and the second part are arranged at two sides of the first central line, the third part is arranged between the first part and the second part, the first part covers a first field oxide layer, the second part covers a second field oxide layer, a first grid oxide layer is formed between the third part and the P-type substrate, the MOS device also comprises a first N well region and a second N well region, the first N well region and the second N well region are respectively arranged at two sides of the poly-silicon layer, are symmetrically arranged about the first central line and are arranged on the P-type substrate, the first field oxide layer is arranged on the first N well region, and the second field oxide layer is arranged on the second N well region. By the field-effect transistor MOS substrate, the problem that a field oxide parasitic device also can be conducted to affect an expected function after a high voltage is accessed to a grid is solved.

Description

technical field [0001] The invention relates to the field of semiconductors, in particular to a field effect transistor MOS device. Background technique [0002] For power management chips of field effect transistors (MOS), it is usually necessary to have a high-voltage device that can withstand high voltage and turn on a lower low-voltage device. The high-voltage device is used for power input, and the low-voltage device is used for operation logic. Moreover, high-voltage devices not only require the drain to be able to withstand high voltage, but the gate also needs to withstand high voltage; the gate withstand voltage is usually achieved by increasing the thickness of the gate oxide, but in the process of actual application, when the gate is connected to a high voltage, the traditional The field oxygen parasitic device of the device will also be turned on, causing the device current to suddenly increase, thereby affecting the expected function. Contents of the invention...

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