Germanium silicon heterogeneous crystal transistor with elevated external base area and its making technology

Abstract

The invention discloses a Ge-Si heterojunction transistor with an elevated external base and the preparation technique thereof, pertaining to the field of semiconductor devices and the preparation technology thereof. The heterojunction transistor comprises a collector formed with silicon substrate, a SiGe layer base and an external base, and a polysilicon emitter. A sidewall structure layer is equipped between the emitter and the base electrode, the external base is elevated, and the sidewall structure layer thereof prevents the emitter and the base electrode leaking. By using the technique of elevating the external base and the epitaxial growth technology of the external base, the invention overcomes the drawbacks that the prior injection technique of the external base in the Ge-Si heterojunction transistor technology leads to the serious Boron enhanced diffusion of the intrinsic base under the window of the emitting region, and thereby the invention makes the base wider and the doping changed, and reduces the fT and fmax parameters of devices. Therefore, the direct current and high frequency characteristics of devices are improved greatly.

Description

technical field [0001] The invention belongs to the technical field of semiconductor devices and their preparation, and in particular relates to a germanium-silicon heterojunction transistor with an elevated outer base region and a preparation process thereof. Background technique [0002] SiGe heterojunction transistors are gradually used in the field of microwave circuits due to their excellent high-frequency performance and low cost advantages. The SiGe heterojunction transistor introduces epitaxial silicon-germanium alloy into the base region to reduce the bandgap width of the base region, thereby greatly improving the DC and high-frequency characteristics of the device. [0003] In the original germanium-silicon heterojunction transistor process, the implantation process is used in the outer base region, and the defects generated by the implantation will lead to serious boron-enhanced diffusion in the intrinsic base region under the emitter window, which will cause the ...

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Problems solved by technology

[0003] In the original germanium-silicon heterojunction transistor process, the outer base region adopts the implantation process, and the defects generated by the implantation will lead to serious boron-enhanced diffusion in the intrinsic base region under the emitter window, which will cause the base region to widen and the doping to change. , while reducing the f of the device T and f max and other parameters

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