Surface passivation method of germanium base substrate

Abstract

The invention discloses a germanium-base substrate surface passivation method, which comprises the following steps of: cleaning a surface of a germanium-base substrate; putting the cleaned germanium-base substrate into a plasma cavity; utilizing reaction gas corresponding to multiply-bound atoms to generate a plasma; carrying out plasma bath processing on the surface of the germanium-base substrate; and applying a guiding electric field in a plasma bath processing process to guide the plasma to drift to the surface of the germanium-base substrate. Due to the processing, covalently joint of activated the multiply-bound atoms and germanium surface atoms is formed, but an interface layer containing germanium compounds is not generated, so that a surface dangling bond is passivated, the probability that the germanium surface atoms are separated from the surface of the germanium-base substrate to be dispersed is reduced, and simultaneously, the phenomenon that the thinning of the EOT is unfavorable as the interface layer is introduced is avoided. In addition, the guiding electric filed is applied, so that the formation of germanium oxides can be effectively suppressed, the passivation efficiency is improved, and the density of interfacial states is reduced.

Description

technical field [0001] The invention belongs to the field of semiconductor devices, and in particular relates to a semiconductor surface passivation method. Background technique [0002] As the silicon-based Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) shrinks to the nanometer scale, the traditional method of improving performance and integration by reducing device size is facing the dual limit test of physics and technology. In order to further improve device performance, one of the effective methods is to introduce high-mobility channel materials. Due to the high electron and hole mobility at the same time (at room temperature (300K), the electron mobility of the germanium channel is 2.4 times that of silicon, and the hole mobility is 4 times that of silicon), germanium materials and germanium-based devices have become an option. [0003] At present, in the preparation technology of germanium-based MOS devices, the interface problem between the germanium su...

AI Technical Summary

Problems solved by technology

One is to use H passivation and Cl passivation in traditional silicon technology to passivate the surface dangling bonds to reduce the interface state, but studies have shown that the passivation effect of this method, such as the formation of Ge-H, Ge-Cl bond chemistry Poor stability, easy to break, unable to effectively suppress the outdiffusion of germanium surface atoms

The second is to insert an ultra-thin layer at the interface between the germanium substrate and the gate dielectric, which can be a dielectric or a semiconductor epitaxial layer, such as SiO 2 、GeO x N y , Si, etc., but this method is not conducive to the reduction of the equivalent gate oxide thickness (EOT)

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