Laterally diffused metal oxide semiconductor field effect transistor

Abstract

The invention provides a laterally diffused metal oxide semiconductor field effect transistor. The laterally diffused metal oxide semiconductor field effect transistor comprises a bottom semiconductorlayer, a first insulating layer, a first top semiconductor layer, a second insulating layer, a second top semiconductor layer, a first conductive type well region, a second conductive type drain region, a second conductive type source region and a gate region structure; a drift region is arranged between the well region and the drain region; a super-junction structure is formed in the drift region; a second conductive type doped buried layer with the doping concentration gradually increased from the second conductive type source region to the second conductive type drain region is arranged inthe first top semiconductor layer. According to the laterally diffused metal oxide semiconductor field effect transistor of the invention, the N type gradient doped layer is formed in the first top semiconductor layer; the doping concentration of the N type gradient doped layer is gradually increased from the source region to the drain region; redundant N type carriers can be induced on an interface close to the second insulating layer; the concentration of the redundant N type carriers is gradually increased from the source region to the drain region; and therefore, the problem of insufficient N type carrier concentration caused by a substrate-assisted depletion effect can be effectively solved.

Description

technical field [0001] The invention belongs to the field of design and manufacture of semiconductor integrated circuits, in particular to a lateral diffusion metal oxide semiconductor field effect transistor. Background technique [0002] Lateral Double-diffused MOSFET (LDMOS) is a multi-sub-device, because of its good turn-off characteristics, high input impedance, and easy compatibility with large-scale integrated circuits, it is widely used in many fields. It is widely used instead of traditional bipolar devices. The most important goal of LDMOS optimal design is to obtain the maximum breakdown voltage while the on-resistance is as small as possible. Since the product of the doping concentration of the conductive layer and the thickness of the conductive layer of this type of multi-sub-device is equal to a constant, these two parameters are often contradictory, and a high breakdown voltage will inevitably lead to a high on-resistance. However, the key to obtaining the ...

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Problems solved by technology

[0007] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a laterally diffused metal-oxide-semiconductor field-effect transistor, which is used to solve the shock of super-junction LDMOS devices caused by the substrate-assisted depletion effect in the prior art. The problem of lowering the breakdown voltage

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