PN junction variodenser in BiCMOS (bipolar complementary metal oxide semiconductor) process and manufacturing method thereof

Abstract

The invention discloses a PN junction variodenser in a BiCMOS (bipolar complementary metal oxide semiconductor) process and a manufacturing method thereof. The PN junction variodenser adopts a germanium silicon growth front definition window with a positive trapezoid shape, so that a germanium silicon layer of a P-type region is of a polycrystalline structure, thus the doping content of the P-type region can be improved, and the electronic emission efficiency is improved when a device is in forward bias. The PN junction variodenser provided by the invention adopts an advanced deep hole contacting process and an N-type spurious buried layer process, the area of an active region is greatly saved, and the width of the active region can be reduced to 0.3 micrometer; and N-type spurious buriedlayers on two sides of the active region can be fully connected, thereby reducing the parasitic NP junction effect, reducing the N end connecting resistance of the device and improving the current density. The invention also discloses a manufacturing method of the PN junction variodenser in the BiCMOS process.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a PN junction varactor in a BiCMOS process, and also relates to a manufacturing method for a PN junction varactor in a BiCMOS process. Background technique [0002] The P terminal of the varactor in the existing BiCMOS process is formed by a single crystal silicon diffusion process, and the extraction of the N terminal usually needs to be realized through the buried layer or well under the shallow trench isolation (STI) and the active region connected to it. This approach is determined by the vertical structure characteristics of its devices. Its disadvantages are that the electron emission efficiency of the PN junction is low, the device area is large, and the connection resistance is large. Moreover, the existence of the active region leading out to the N-terminal and the isolation between the N-terminal and the P-terminal must be separated by STI ...

AI Technical Summary

Problems solved by technology

The disadvantage is that the PN junction electron emission efficiency is low, the device area is large, and the connection resistance is large

Moreover, the existence of the active region leading to the N-terminal and the isolation between the N-terminal and the P-terminal must be separated by STI or other field oxygen, which also limits the further reduction of the device size.

Existing varactors are not suitable for output devices in high-frequency circuits

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