Forming method of radio frequency switching device and radio frequency switching device

Abstract

The invention provides a method for forming a radio frequency switching device and a radio frequency switching device, forming a gate structure on a substrate, and sequentially forming an etching stop layer, a first dielectric layer, a silicon nitride layer and a silicon nitride layer on the gate structure and the substrate. After the second dielectric layer, an air gap is formed in the silicon nitride layer. Since the air gap is relatively the lowest in dielectric constant, the existence of the air gap makes the final layer in the second dielectric layer Parasitic capacitances between the source metal layer formed on the second dielectric layer and the gate structure and between the drain metal layer formed on the second dielectric layer and the gate structure are minimized, thereby reducing the off-capacitance Coff, improving the performance of RF switching devices.

Description

technical field [0001] The invention relates to the technical field of semiconductor integrated circuit manufacturing, in particular to a method for forming a radio frequency switch device and the radio frequency switch device. Background technique [0002] The radio frequency switching device is a device used for signal switching in the communication field. It has the advantages of simple structure, wide application range, low cost, low power consumption, easy installation, and high reliability. It can be widely used in carrier telephone switching, cable television signal Switching, cable TV signal switch and other fields, when it is working, some areas are in the on state, and some areas are in the off state. [0003] The quality factor FOM (Figure Of Merit) is used to evaluate the switching performance or process capability of the field effect transistor MOSFET. It is a compromise between Insertion Loss and Isolation. The insertion loss is characterized by the on-resistan...

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Problems solved by technology

[0004] For RF switching devices, it mainly includes source, drain and gate. Generally, parasitic capacitance will be generated between drain and gate, and at the same time, parasitic capacitance will also be generated between source and gate. Parasitic capacitance The presence of will lead to an increase in the off-capacitance Coff, which will lead to an increase in the quality factor FOM, making the performance of the RF switching device worse

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