High voltage power LDMOS device and manufacture method thereof

Abstract

The embodiment of the invention discloses a high voltage power LDMOS(Lateral Double-diffuse MOS)device and a manufacture method thereof. The said high voltage power LDMOS device includes: a substrate; a gradual change drift region which is located within the substrate, wherein a drain terminal well region and a source well region with same mixed type are connected with each other and the depth of the drain terminal well is deeper than that of the source well region, wherein the gradual change drift region comprises a drain terminal well region and a source terminal well region that have the same doping type and are communicated with each other, and the depth of the drain terminal well region is greater than that of the source terminal well region; and a filed oxidation layer is located above the gradual drift region. The high voltage power LDMOS device and the manufacture method thereof provided by the invention are advantaged by simple process and low cost. Besides, the process procedure is easily controlled, such that some key parameters such as the breakdown voltage and on-resistance of appliances can be steady.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, and more specifically, to a high-voltage power LDMOS device and a manufacturing method thereof. Background technique [0002] The manufacture of LDMOS (Lateral Double-diffuseMOS) devices mainly uses double-diffusion technology, and two boron-phosphorus diffusions are successively performed in the same active area. The difference in junction depth is used to precisely control the length of the channel. In LDMOS devices, there is a high-resistance layer between the source region and the drain region, which is called a drift region (drift). The existence of the drift region increases the breakdown voltage of the device, and reduces the parasitic capacitance between the source and the drain, which is beneficial to improve the frequency characteristics. At the same time, the drift region acts as a buffer between the channel and the drain, weakening the short-channel effect of the...

AI Technical Summary

Problems solved by technology

[0007] These two methods of forming the drift region have their own disadvantages: the former requires a lot of time in addition to high requirements on manufacturing equipment, which brings difficulties to mass production, complicated process and high cost.

The latter has two problems due to the large thickness and low concentration of the epitaxial layer: first, the thick epitaxial layer will cause pattern distortion, which will cause difficulties in the lithography alignment of the subsequent process. Second, low-concentration epitaxy is difficult to control, causing key parameters such as breakdown voltage and on-resistance of high-voltage power LDMOS devices to fluctuate with fluctuations in epitaxy layer concentration

[0009] It can be seen from the above that the formation of high-voltage power LDMOS devices through the existing process has the disadvantages of complex process, high cost, difficult process control, and unstable key parameters such as breakdown voltage and on-resistance of the device.

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