Method for controlling growth effect of facet of silicon-germanium (Si-Ge) alloy

Abstract

The invention discloses a method for controlling growth effect of a facet of silicon-germanium (Si-Ge) alloy. The method comprises the following steps: a collecting electrode and a secondary collecting electrode are sequentially formed on a silicon substrate, a pad oxide film and a silicon nitride film sequentially grow on the secondary collecting electrode, an active area is photo-etched to forma trench, and an isolation medium film grows to form a shallow trench isolation (STI) structure; the isolation medium film at the STI edge is etched to be under the silicon nitride film by reverse photoetching; the silicon nitride film and the pad oxide film are removed; and a base SiGe film grows. In the invention, after the oxide film for an STI process grows completely, design rules of a mask for the common reverse etching are modified, and an etching area for a Ge-Si heterojunction bipolar transistor area is expanded to the outside of the active area, so an oxide film indentation structure at the edge of a shallow trench is obtained without increasing the process cost.

Description

technical field [0001] The invention relates to a manufacturing process method of a semiconductor integrated circuit, in particular to a method for controlling the facet growth effect of a silicon-germanium alloy (SiGe). Background technique [0002] Since SiGeBiCMOS (silicon germanium bipolar complementary metal oxide semiconductor) has good compatibility with CMOS technology and can meet the requirements of high speed and low noise, it has more and more applications in the field of radio frequency. [0003] The existing SiGeBiCMOS manufacturing process method is to directly integrate germanium-silicon heterojunction bipolar transistors on the basis of CMOS technology, such as figure 1 shown. In this case, since SiGe will be directly deposited on the edge of STI (Shallow Trench Isolation), and SiGe will grow into a single crystal in the active area, and will deposit polysilicon on the oxide film, single crystal SiGe and polysilicon A facet is formed between the SiGe cryst...

AI Technical Summary

Problems solved by technology

For germanium-silicon heterojunction bipolar transistors, in order to obtain high-performance device characteristics, although the above method can reduce the base resistance and reduce the defects in the growth of the germanium-silicon base region, it will inevitably increase the cost of implementation.

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