An ultra-thin lateral double-diffused metal oxide semiconductor field effect transistor and its preparation method

Abstract

The invention discloses an ultrathin transverse double diffusion metal-oxide semiconductor field-effect transistor which comprises a P-type substrate. An oxide buried layer is arranged on the P-type substrate, an N-type well region and a P-type well region are arranged on the oxide buried layer, an N-type buffering region is arranged inside the N-type well region, a field oxide is arranged on the N-type well region, an N-type draining region is arranged inside the N-type buffering region, and a P-type contact region and an N-type source region are arranged inside the P-type well region. A P-type well region array composed of P-type well region units is arranged below the field oxide, and is located between the N-type buffering region and the P-type well region. The width of each P-type well region unit gradually becomes large from the N-type buffering region to the P-type well region. The capability for resisting the high-voltage parasitic effect of the ultrathin transverse double diffusion metal-oxide semiconductor field-effect transistor in an electrical level shift circuit is greatly enhanced, and the performance of an intelligent power module can be greatly improved. The invention further discloses a method for preparing the ultrathin transverse double diffusion metal-oxide semiconductor field-effect transistor.

Description

technical field [0001] The invention relates to a power semiconductor device, in particular to an ultra-thin lateral double-diffused metal oxide semiconductor field effect transistor used in a level shift circuit. Background technique [0002] Intelligent power modules in high-voltage power integrated circuits can be used in various fields, such as driving and controlling various industrial and residential, single-phase and three-phase motors. The level shift circuit in the intelligent power module provides the output voltage for the high-voltage output circuit, which has become a key part of the entire intelligent power module. The LDMOS used as the switching element in the level shift circuit has high withstand voltage, simple driving circuit, and fast switching speed Fast and other advantages. Because of this, LDMOS has been frequently used in power integrated circuits in recent years. However, when LDMOS is used in a level shift circuit, the drain of LDMOS needs to lea...

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Problems solved by technology

[0004] The invention provides an ultra-thin silicon-on-insulator LDMOS that is resistant to the influence of high-voltage interconnect lines. The invention solves the problem of high-voltage parasitic effects caused by high-voltage interconnect lines in level shift circuits, without sacrificing the breakdown voltage Successfully lead out the drain metal connection of LDMOS

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