A high-frequency horizontal double-diffused oxide semiconductor device and its manufacturing method

Abstract

The invention relates to a high-frequency horizontal double diffusion oxide semiconductor device and a manufacturing method thereof. The method comprises the steps that a pad oxide layer with a first preset thickness is generated on the upper surface of an epitaxial layer; a sinking area is defined in a first default area on the pad oxide layer and a groove with a preset depth is formed in the pad oxide layer in the sinking area; the bottom part of the groove is located in the oxide layer; sinking area ion implantation is carried out in the groove to form the sinking area; and silicon nitride is deposited on the upper surface of the pad oxide layer and then an active region is defined by employing the groove as an alignment mark and is prepared. The relatively thick oxide layer is formed on the epitaxial layer, the groove is formed in the oxide layer through etching, and the groove is taken as the alignment mark of forming a sinking layer, so that a fault is prevented from being formed in an ion implantation area in a traditional technology; the on resistance of the device is reduced; and the lattice defect is avoided.

Description

technical field [0001] The invention relates to the technical field of semiconductor devices, in particular to a high-frequency horizontal double-diffused oxide semiconductor device and a manufacturing method thereof. Background technique [0002] High-frequency horizontal double-diffused metal-oxide semiconductor (RF LDMOS) is widely used in mobile phone base stations, radio and television and radar and other fields. Such as figure 1 As shown, the existing N-type RF LDMOS process generally includes preparing a P sinker layer 30, a source layer 50, a polysilicon layer 60, a body region layer 70, a drift layer 80, a drain layer 90, and a P+ layer on a P-type epitaxial layer 20. Injection layer 40 etc. The working principle of the RF LDMOS device is that the sinker layer 30 is connected to the source layer 50 through the P+ injection layer 40, and the P+ injection layer 40 and the source layer are short-circuited through the metal of the contact hole. After the channel unde...

AI Technical Summary

Problems solved by technology

Although sinking ion drive would reduce this effect, there is still a risk

This risk makes the on-resistance of the device unstable and tends to be large

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