RFLDMOS (Radio Frequency Laterally Diffused Metal Oxide Semiconductor) based on self-aligned silicide and tungsten plug structure and manufacturing method thereof

Abstract

The invention discloses an RFLDMOS (Radio Frequency Laterally Diffused Metal Oxide Semiconductor) based on a self-aligned silicide and tungsten plug structure and a manufacturing method thereof. By utilizing a double-diffusion method, a source high-doping area and a drain high-doping area which have lateral channel structures are manufactured on a silicon slice, and a multicrystal silicon grid ismanufactured; the manufacturing method of the RFLDMOS based on the self-aligned silicide and tungsten plug structure is characterized by further carrying out the following treatments: forming a silicon dioxide layer on the surface; etching off parts of the silicon dioxide layer at the tops of a source and a drain, and depositing a layer of metal on the whole surface of the silicon slice; carryingout high-temperature annealing treatment to form a metal silicide in a silicon-exposed area on the silicon slice surface; manufacturing a dummy faraday gate above the multicrystal silicon grid, manufacturing an oxide dielectric layer on the whole silicon slice surface, manufacturing through holes communicated to the metal silicide at parts corresponding to metal silicide contact holes, and filling tungsten in the through holes; and arranging metal layers respectively corresponding to the through holes of the source and the drain to form a contact electrode. According to the RFLDMOS based on the self-aligned silicide and tungsten plug structure and the manufacturing method thereof disclosed by the invention, the series impedance of a source end is reduced, and the power gain of devices is effectively increased.

Description

technical field [0001] The invention relates to an LDMOS device, in particular to a high-power RFLDMOS device and a method for preparing the device. Background technique [0002] RFLDMOS devices are improved n-channel MOSFETs designed for radio frequency power amplifiers, and are integrated high-power solid-state microwave power semiconductor devices that integrate microelectronic integrated circuits and microwave technology. LDMOS has a lateral channel structure, and the drain, source and gate are all on the chip surface. Double diffusion technology is adopted, and boron and phosphorus are diffused twice in the same photolithographic window. The difference in the lateral junction depth of the two impurity diffusions can be accurately Determine the channel length. Due to its high breakdown voltage, good linearity, high efficiency and low price, it is intensively used in high-frequency and high-power devices such as mobile communication base stations and airborne radars. ...

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Problems solved by technology

[0003] With the gradual reduction of the feature size of the processing technology, the electrical contact cross-section between the source, drain and gate regions of the device and the metal layer is very small, and the small contact area leads to a large increase in contact resistance, which in turn leads to a decrease in the performance of the power chip.

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