Radio-frequency LDMOS (laterally diffused metal oxide semiconductor) device and manufacturing method thereof

Abstract

The invention discloses a radio-frequency LDMOS (laterally diffused metal oxide semiconductor) device. A semiconductor region and a drift region are arranged in an epitaxial layer; a source region is arranged in the semiconductor region; a drain region is arranged in the drift region; a liner oxidation layer is arranged above part of the drift region or above part of the drift region and part of the epitaxial layer; a grid oxidation layer is arranged above part of the source region and part of the semiconductor region or above part of the source region, part of the semiconductor region and part of the epitaxial layer; the liner oxidation layer is thicker than the grid oxidation layer; a polycrystalline silicon grid is arranged above the liner oxidation layer and the grid oxidation layer; the grid consists of a main body, a first extension part and a second extension part; the main body of the grid is only located above the grid oxidation layer, and both the extension parts of the grid are only located above the liner oxidation layer. The invention further discloses a manufacturing method of the radio-frequency LDMOS device. With the adoption of the radio-frequency LDMOS device and the manufacturing method thereof, the reliability of the grid can be improved, the IGSS failure is eliminated, and the yield of the devices is increased.

Description

technical field [0001] The present application relates to a semiconductor integrated circuit device, in particular to a radio frequency LDMOS (Laterally Diffused MOS Transistor) device. Background technique [0002] see figure 1 , which is an existing RF LDMOS device. There is a lightly doped p-type epitaxial layer 2 on a heavily doped p-type substrate 1 . In the epitaxial layer 2 there is a p-type body region 3 and an n-type drift region 6, the sides of which may or may not be in contact. The body region 3 has a heavily doped n-type source region 4 and a heavily doped p-type body region lead-out region 5, and the sides of the two are in contact. The body region lead-out region 5 is used to lead the body region 3 out. In the drift region 6 there is a heavily doped n-type drain region 7 . There is a gate oxide layer 8 extending from part of the source region 4 to the drain region 7, and its bottom surface contacts the active region 4, the body region 3, and the epitaxial...

AI Technical Summary

Problems solved by technology

[0004] However, the respective extensions 9b, 9c of the gate are placed on the gate oxide layer 8, and after a long period of use, the metal silicide 12 above the respective extensions 9b, 9c of the gate may reach along the grain boundaries of polysilicon. underneath the gate oxide 8

If the gate oxide layer 8 is thinner, there is a risk of breakdown of the gate 9 and drain region 7, which will also lead to the failure of IGSS (gate-source leakage current)

Images