Method for cleaning germanium sheet and passivating surface of germanium sheet

Abstract

The invention discloses a method for cleaning a germanium sheet and passivating the surface of the germanium sheet. The method comprises: selecting the germanium sheet, putting the germanium sheet into acetone and ethanol solutions to clean by ultrasonic wave respectively so as to remove organic pollutant on the surface of the germanium sheet; cleaning the germanium sheet by hydrochloric acid solution and deionized water to remove irregular intrinsic germanium oxide thin films and metal ions remained on the surface of the germanium sheet; putting the germanium sheet into mixed solution of hydrogen peroxide and ammonium hydroxide to generate a layer of germanium oxide thin film on the surface of the germanium sheet as a sacrificial layer, and thus removing defects on the surface of the germanium sheet; passivating the germanium sheet by hydrochloric acid solution so as to modify dangling bonds on the surface of germanium by helium atoms, and thus obtaining stable germanium surface. The method for cleaning the germanium sheet and passivating the surface of the germanium sheet has the advantages of simple operation, convenience to use, low cost and obvious passivation effect.

Description

technical field [0001] The invention relates to a method for cleaning and surface passivation of a germanium sheet, belonging to the technical field of semiconductor electronic materials and device manufacturing. Background technique [0002] As the core and foundation of the information industry, semiconductor technology is an important symbol to measure a country's scientific and technological progress and comprehensive national strength. In the past 40 years, silicon-based integration technology has followed Moore's law to increase the working speed of devices, increase integration and reduce costs by reducing the feature size of devices. The feature size of silicon-based CMOS devices has been reduced from micrometers to nanometers. However, when the gate length of MOS devices is reduced to less than 90 nanometers, the thickness of the gate dielectric (silicon dioxide) has been gradually reduced to close to 1 nanometer, and physical limitations such as increased off-state...

AI Technical Summary

Problems solved by technology

[0004] The traditional treatment of silicon surface with hydrofluoric acid (HF) solution has good properties, but the same scheme can not be transplanted to germanium (Ge) surface to obtain ideal results.

First, the polarity of the HF solution is very strong, which may destroy the surface morphology of the substrate during the surface etching process; in addition, the HF solution cannot remove the oxides on the surface well, and the oxides remaining on the surface make it difficult to process During the process, the surface dangling bonds cannot be well modified; finally, after HF solution treatment, a Ge-H bond is formed on the surface of the germanium sheet, which will be oxidized again to obtain GeO after being exposed to the air for a short time. x layer, again contaminating the cleaned germanium surface

Moreover, due to the small bond energy of Ge-H, it is easy to break when heated during the process

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