Radio frequency ldmos device and manufacturing method thereof

Abstract

The invention discloses a radio frequency laterally diffused metal oxide semiconductor (LDMOS) component which comprises a metal plug and a field oxide layer which is arranged below top layer metal of a drain electrode region and is thick. The resistance of the metal plug is small, and therefore parasitic resistance of the component can be reduced. The thick field oxide layer can reduce the parasitic resistance of the component, and therefore frequency characteristic of the component can be improved. Meanwhile, the metal plug has the advantage of non-transverse diffusion, and therefore the area of the component can be reduced. Due to the fact that the thickness of the field oxide layer can be improved and the thickness of an inter-lamination layer can be relatively reduced, the number of layers of the metal layers can be reduced, and cost of the component can be reduced. The invention further discloses a manufacturing method of the radio frequency LDMOS component.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a radio frequency LDMOS (Laterally Diffused Metal Oxide Semiconductor) device. The invention also relates to a manufacturing method of the radio frequency LDMOS device. Background technique [0002] RF LDMOS is a device with a very good market. Especially with the wide application of communication technology, it will get more and more attention as a new type of power device. [0003] Such as figure 1 Shown is a schematic structural diagram of an existing radio frequency LDMOS device; the basic structure of an existing radio frequency LDMOS device includes: [0004] The P+ silicon substrate 101 is the substrate doped with high-concentration P-type impurities and the P- epitaxial layer 102 formed above the P+ silicon substrate; the resistivity of the P+ silicon substrate 101 is 0.01 ohm·cm-0.02 ohm cm, the thickness and doping concentration of the P...

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Problems solved by technology

However, although the use of P+ polycrystalline has improved the characteristics of the above two aspects, it has two problems: one is that the P+ polycrystalline process has not been widely used due to the process control problem, and the maturity of the process is still problematic; the other is that After using it, the diffusion problem still exists, and the resistance is still very high, such as much higher than the metal resistance

[0014] Another defect of the existing radio frequency LDMOS device is that the drain D is the top layer metal, and the thicker the thickness of the dielectric film between the drain D and the P- epitaxial layer 102, the parasitic capacitance between the drain D metal and the substrate The smaller the thickness, the dielectric film here can be field oxygen, a combination of field oxygen and interlayer film, but the thickness of general field oxygen is difficult to achieve more than 2 microns, so the drain D has a large parasitic capacitance

If the parasitic capacitance is reduced by thickening the interlayer film, it is generally necessary to increase the number of metal layers, which will increase the process cost

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