SOI (silicon-on-insulator) super-junction LDMOS (Laterally Diffused Metal Oxide Semiconductor) device with buffer layer

Abstract

The invention discloses an SOI (silicon-on-insulator) super-junction LDMOS (Laterally Diffused Metal Oxide Semiconductor) device with a buffer layer, which comprises an SOI substrate and an active region positioned on the SOI substrate, wherein the active region comprises a gate region, a source region and a drain region which are respectively positioned at both sides of the gate region, a body region positioned under the gate region and a drift region positioned between the body region and the drain region; and the drift region comprises a lateral super-junction structure and a buffer layer positioned above the lateral super-junction structure. By arranging the buffer layer above the drift region, the invention can relieve the influence of the auxiliary depletion effect of the substrate on the charge balance in the SOI super-junction LDMOS drift region, improve the breakdown voltage of the device and greatly shallow the doping depth in the buffer layer manufacturing process, thereby reducing the impurity injection energy, facilitating the uniform distribution of impurities in the drift region and greatly lowering the process difficulty.

Description

technical field [0001] The invention relates to a lateral double-diffused metal oxide semiconductor (LDMOS, LateralDouble-diffused MOSFET) device structure, in particular to an SOI superjunction LDMOS device with a buffer layer, belonging to the technical field of microelectronics and solid electronics. Background technique [0002] Lateral Double-diffused MOSFET (LDMOS, Lateral Double-diffused MOSFET) is the key technology of high-voltage integrated circuit HVIC (High Voltage Integrated Circuit) and power integrated circuit PIC (Power Integrated Circuit). Its main feature is that a relatively long lightly doped drift region is added between the channel region and the drain region. The doping type of the drift region is consistent with that of the drain end. By adding the drift region, it can share the breakdown voltage. [0003] The so-called super-junction LDMOS is an improved LDMOS, that is, the low-doped N-type drift region of the traditional LDMOST is replaced by a set ...

AI Technical Summary

Problems solved by technology

[0006] However, if a design requires thick-film SOI (thickness t si >1.5um), the introduction of a buffer layer can alleviate the substrate-assisted depletion effect of SOI lateral superjunction devices, but since the buffer layer is located on the buried oxide layer below the drift region, it is necessary to achieve such an implantation depth during ion implantation , not only the implantation energy must be very large, but also the impurity distribution must be precisely controlled, and the process is very difficult to realize

Images