Vertical parasitic PNP transistor in silicon-germanium BICMOS (Bipolar Complementary Metal Oxide Semiconductor) technique and fabrication method

Abstract

The invention discloses a vertical parasitic PNP transistor in the silicon-germanium BICMOS technique. A groove which is in contact with a base region is formed in a shallow trench field oxide around the base region, the depth of the groove is smaller than or equal to the depth of the base region, polycrystalline silicon is filled in the groove and doped with N-type dopant, the polycrystalline silicon doped with the N-type dopant is formed into an outer base region, which is in contact with the side of the base region, and a metal contact is formed on the outer base region, and leads out a base. The invention also discloses a fabrication method for the vertical parasitic PNP transistor in the silicon-germanium BICMOS technique. The vertical parasitic PNP transistor can be used as an output device in a high-speed, high-gain HBT (heterojunction bipolar transistor) circuit, so that one more type of device is provided as an option for the circuit, the area of the device can be effectively reduced, the parasitic effect of the device can be effectively decreased, the collector resistance of the PNP transistor can be effectively decreased, and the performance of the device can be effectively enhanced; and the method does not need additional process conditions, and can reduce the production cost.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a vertical parasitic PNP transistor in a silicon-germanium BICMOS process, and also relates to a method for manufacturing a vertical parasitic PNP transistor in a silicon-germanium BICMOS process. Background technique [0002] In RF applications, higher and higher device characteristic frequencies are required. BiCMOS (Bipolar CMOS) is a technology in which CMOS and bipolar devices are integrated on the same chip at the same time. In BiCMOS process technology, NPN triodes, especially silicon germanium (SiGe) heterojunction triodes (HBT) or germanium silicon carbon heterogeneous Junction triode (SiGeC HBT) is a good choice for UHF devices. And the SiGe process is basically compatible with the silicon process, so SiGe HBT has become one of the mainstreams of UHF devices. In this context, the requirements for the output device are correspondingly incre...

AI Technical Summary

Problems solved by technology

The disadvantage is that the device area is large and the connection resistance of the collector is large

Since the extraction of the collector electrode in the prior art is realized through another active region adjacent to the collector region, and the other active region and the collector region need to be isolated by STI or other field oxygen, such This greatly limits the further reduction of the device size

Images