Semiconductor structure with suspended sources and drains as well as formation method thereof

Abstract

The present invention proposes a semiconductor structure, comprising: a Si substrate; a plurality of protruding structures formed on the Si substrate, wherein there is a certain gap between every two protruding structures; A suspended thin layer between the structures and connected to the top of the two raised structures; a transition layer formed on the suspended thin layer; a high-mobility III-V group compound material formed on the transition layer layer; and a gate stack formed over the layer of III-V compound material, and a source and a drain formed in the layer of III-V compound material. Since the thin layer of the first semiconductor material is very thin, the dislocation density between it and the transition layer can be greatly reduced. In addition, since the raised structure can release part of the thermal mismatch stress, the growth quality of the transition layer can be guaranteed, and The transition layer can be made very thin.

Description

technical field [0001] The invention relates to the technical field of semiconductor design and manufacture, in particular to a semiconductor structure with suspended sources and drains and a forming method thereof. Background technique [0002] For a long time, in order to obtain higher chip density, faster working speed and lower power consumption. The feature size of Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs) has been continuously scaling down in accordance with the so-called Moore's law, and their operating speeds are getting faster and faster. At present, it has entered the range of nanoscale. However, a serious challenge that comes with it is the short channel effect, such as subthreshold voltage drop (Vtroll-off), drain-induced barrier lowering (DIBL), source-drain punch through, etc. The off-state leakage current of the device is significantly increased, resulting in performance degradation. In addition, for devices using III-V compound materials...

AI Technical Summary

Problems solved by technology

However, the current transition layer is relatively thick, and the defect density is high, which seriously affects the performance of the device.

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