Vertically-overlapped back grid type Si-NWFET (Nano Wire Field Effect Transistor) manufacturing method based on SOI (Silicon On Insulator)

Abstract

The invention provides a preparation method of a vertically-overlapped back grid type silicon nano wire field effect transistor based on an SOI (Silicon On Insulator). The preparation method comprises the following steps of: alternatively depositing a silicon layer and a germanium-silicon layer on the SOI to form a fin-shaped active region, and forming a silicon nano wire in the fin-shaped active region; forming an isolating medium layer between source drain regions; forming a grid electrode oxidization layer on the surface of the silicon nano wire; and finally, forming a grid electrode on an SOI substrate in the fin-shaped active region. Due to the presence of an insulator layer in the SOI, the isolation effect between the grid electrode and the SOI substrate is effectively increased; a process for forming the grid electrode oxidization layer on the silicon nano wire is independently carried out so that the conventional grid electrode oxidization layer is adopted; and the grid electrode is formed after ions are injected into the source drain regions, namely a back grid electrode process is adopted, so that the preparation method is good for controlling an outline of the grid electrode and an electrical property of a device. Furthermore, a silicon nano wire field effect transistor structure is designed by a vertically-overlapped back grid type silicon nano wire structure; and the quantity of nano wires is increased and the current driving capability of the device can be increased.

Description

technical field [0001] The invention relates to the field of integrated circuit manufacturing, in particular to an SOI-based vertically stacked back-gate Si-NWFET manufacturing method. Background technique [0002] It has always been the goal pursued by the development of microelectronics industry to increase the working speed and integration of chips and reduce the power consumption density of chips by reducing the size of transistors. In the past forty years, the development of microelectronics industry has been following Moore's Law. At present, the physical gate length of field effect transistors is close to 20nm, and the gate dielectric is only a few layers of oxygen atoms thick. It is difficult to improve performance by reducing the size of traditional field effect transistors, mainly because of the short Channeling and gate leakage destroy the switching performance of transistors. [0003] Nanowire Field Effect Transistor (NWFET, Nano-Wire MOSFET) is expected to sol...

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Problems solved by technology

[0009] This method can realize the vertically stacked silicon nanowire field effect transistor structure, but there is a disadvantage: when the silicon germanium layer is oxidized, the germanium will be concentrated on the surface of the silicon layer, and the SiO2 will be removed. 2 Finally, a layer of concentrated silicon-germanium alloy is coated on the surface of Si-NW

Since germanium dioxide is soluble in water, the subsequent process faces great inconvenience. In addition, the dielectric constant of germanium dioxide is smaller than that of silicon dioxide, and the interface state between germanium dioxide and silicon is relatively large, so it is not suitable for gate oxidation of MOSFET. Floor

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