Source region of LDMOS (Laterally Diffused Metal Oxide Semiconductor) device and manufacturing method thereof

Abstract

The invention discloses a source region of an LDMOS (Laterally Diffused Metal Oxide Semiconductor) device, which is in the shape of a dumbbell. The source region comprises a rectangular intermediate region and two polygonal terminal regions, wherein the width of the rectangular intermediate region of the source region in the channel direction is a'; the minimum width of each polygonal terminal region of the source region in the channel direction is c', the minimum width in the direction perpendicular to the channel direction is d', c'>=a', and d'>=a'. The invention also discloses a manufacturing method of the source region of the LDMOS. By changing the two terminal regions of the source region of the LDMOS device from the traditional semicircles to polygons, the invention ensures that the ion implantation shadow effect can not be produced in the source region manufacturing process, thereby being beneficial to improving the breakdown voltage of the LDMOS device.

Description

technical field [0001] The invention relates to an LDMOS (laterally diffused MOS, laterally diffused MOS transistor) device. Background technique [0002] see figure 1 , which is a schematic cross-sectional view of an existing LDMOS. There is an n-type buried layer 11 on the p-type substrate 10 , and there is an n-well 12 further above. The depth of the n-well 12 is usually greater than 2 μm, and is also called a deep n-well. There are multiple isolation regions 13 in the n well 12, and these isolation regions 13 isolate the n well 171 and the p well 172 in the n well 12 from each other. There is an n-type heavily doped region 181 in the n well 171, which serves as the drain of the LDMOS device. The p-well 172 has an n-type heavily doped region 182 and a p-type heavily doped region 183, which are connected to serve as the source of the LDMOS device. The p-well 172 is the source region of the LDMOS device. There is a gate oxide layer 14 on the n-well 12, and a gate 15 o...

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Problems solved by technology

Apparently, the ion implantation process with an oblique angle has a shadow effect of ion implantation in the region at both ends of the cavity 151, which will lead to uneven doping at both ends of the formed p-well 172, and even weak spots, which eventually lead to LDMOS The breakdown voltage of the device is limited

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