Manufacturing method of lateral double-diffused transistor

Abstract

The invention relates to the technical field of semiconductor power devices. The invention provides a manufacturing method of a lateral double-diffusion transistor. A drift region of a first doping type is formed in injection regions on a substrate and an overlapping region between the injection regions by utilizing multiple times of ion implantation (oblique angle implantation); and the doping concentration of the drift region is distributed in a gradient decreasing (linear variable doping concentration) manner from the center of the overlapping region to the two ends along the channel direction, so that a formed device is of a bilaterally symmetrical structure by taking the central axis of the drift region as the center. The breakdown voltage of the device is improved; enough impurity doping concentration is ensured; therefore, the device has relatively small on-resistance; the performance of the formed device is improved; according to the manufacturing method, the phenomenon that aspecially-made mask with a specific window design is used for forming the linear variable doping drift region in the prior art is avoided, the manufacturing cost is saved, and the linear distributionof the doping concentration of the drift region can be controlled by controlling the ion implantation frequency and angle through the process, so that the applicability of the manufacturing method isimproved.

Description

technical field [0001] The invention relates to the technical field of semiconductor power devices, in particular to a method for manufacturing a lateral double-diffused transistor. Background technique [0002] An integrated high-voltage laterally diffused metal oxide semiconductor (LDMOS) device refers to a high-voltage MOS with a lateral channel structure and a drift region. The drain, gate, and source of this type of device are all located on the surface of the chip. It is the most critical integrated device in the horizontal high-voltage BCD process (the process of making bipolar, complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor, CMOS) and DMOS devices on the same chip) platform. In high-voltage interior communications (HVIC), high-voltage LDMOS is generally used as a switching device. For switching devices, how to achieve high blocking withstand voltage and low on-state resistance that meets application requirements is the key to optimiz...

AI Technical Summary

Problems solved by technology

The VLD technology is to obtain a uniform surface electric field by optimizing the distribution of the dopant dose or concentration linear change in the drift region, but because the method of achieving lateral variable doping in the existing process is to make the mask into a specific window, through A certain dopant dose is implanted into the window to form a linear distribution of surface ions, so the key to this technology lies in the fabrication of the mask, which makes the application of VLD technology difficult

Images