LDMOS device with step-like drift region and fabrication method thereof

摘要

An LDMOS device is disclosed. The LDMOS device includes: a substrate having a first type of conductivity; a drift region having a second type of conductivity and being formed in the substrate; a doped region having the first type of conductivity and being formed in the substrate, the doped region being located at a first end of the drift region and laterally adjacent to the drift region; and a heavily doped drain region having the second type of conductivity and being formed in the substrate, the heavily doped drain region being located at a second end of the drift region, wherein the drift region has a step-like top surface with at least two step portions, and wherein a height of the at least two step portions decreases progressively in a direction from the doped region to the drain region. A method of fabricating LDMOS device is also disclosed.

主权项

1. A laterally diffused metal oxide semiconductor (LDMOS) device comprising:
a substrate having a first type of conductivity; a drift region having a second type of conductivity and being formed in the substrate; a doped region having the first type of conductivity and being formed in the substrate, the doped region being located at a first end of the drift region and laterally adjacent to the drift region; a heavily doped drain region having the second type of conductivity and being formed in the substrate, the heavily doped drain region being located at a second end of the drift region; a gate oxide layer and a gate both on a top surface of the substrate, the gate oxide layer covering a portion of the drift region and a portion of the doped region; sidewalls on both sides of the gate oxide layer and the gate; and a heavily doped source region having the second type of conductivity and a heavily doped channel pick-up region having the first type of conductivity both formed in the doped region, the heavily doped channel pick-up region being located at an end of the source region farther from the drift region, wherein the drift region has a step-like top surface with at least two step portions, and wherein a height of the at least two step portions decreases progressively in a direction from the doped region to the drain region.