A lateral double-diffusion mos device

Abstract

The present invention provides a lateral double-diffused MOS device, which includes a first conductivity type semiconductor substrate, a first conductivity type semiconductor body region, a second conductivity type semiconductor drift region, a second conductivity type semiconductor source region, a highly doped first conductivity type Type semiconductor body contact region and gate structure, the gate structure includes a polysilicon gate electrode and a gate oxide layer, and at least two polysilicon islands are provided on the inner upper surface of the drift region of the second conductivity type semiconductor, and the polysilicon islands store uniformly distributed charges; from The direction from the body region of the first conductivity type semiconductor to the drain region of the second conductivity type semiconductor, the distance from the bottom of the polysilicon island to the first conductivity type semiconductor substrate increases successively; the present invention sets a plurality of storage charges with different depths in the drift region The polysilicon island, by changing the amount of charge and the width of the drift region that needs to be depleted, makes the electric field distribution in the drift region more uniform and improves the reverse blocking voltage of the device.

Description

technical field [0001] The invention relates to the technical field of semiconductor devices, in particular to a lateral double-diffusion MOS device. Background technique [0002] Metal oxide power MOS semiconductor devices, with the rapid development of the semiconductor industry, power electronics technology represented by high-power semiconductor devices has developed rapidly, and its application fields have continued to expand, such as the control of AC motors and printer drive circuits. Among various power devices today, laterally diffused MOS devices (LDMOS) have the advantages of high operating voltage and easy integration, so they are widely used. [0003] In the design of LDMOS devices, the breakdown voltage and on-resistance have always been the main goals that people pay attention to when designing such devices. The thickness of the epitaxial layer, doping concentration, and the length of the drift region are the most important parameters of LDMOS. The traditiona...

AI Technical Summary

Problems solved by technology

However, due to the substrate-assisted depletion effect, the effects of RESURF technology and super-junction LDMOS are greatly affected.

The reason is that the potentials at different positions in the drift region are different, so the degree of depletion by the substrate is different. If the drift region adopts a uniform thickness, the optimization of the electric field in the drift region cannot be achieved.

Images