Wet method for passivating surface of germanium monocrystal

Abstract

The invention discloses a wet method for passivating the surface of a germanium monocrystal, which comprises the following steps of: mixing hydrofluoric acid and hydrogen peroxide solution in a volume ratio of (1-4):(4-1); heating the mixed solution to the temperature of between 30 and 80 DEG C; and putting the germanium monocrystal into the mixed solution, and reacting for 30 to 300 seconds, so that a GeOx passivation layer is formed on the surface of the germanium monocrystal. The oxidizability of hydrogen peroxide and the selective dissolubility of the hydrofluoric acid on germanium oxidesare combined organically, so that a good passivation effect is achieved on the surface of the germanium monocrystal. The method is easy to operate and high in efficiency, and the complex operation process of removing the oxides on the surfaces of germanium monocrystal sheets is avoided simultaneously. The method can be used for the passivation of germanium chips for solar cells, complementary metal oxide semiconductor (CMOS) devices and the like in the field of process manufacturing of semiconductor devices.

Description

technical field [0001] The invention relates to a method for passivating the surface of a germanium single crystal, in particular to a method for wet passivating the surface of a germanium single crystal. Background technique [0002] The minority carrier lifetime has always been considered by the industry and academia as one of the important parameters to test the quality of semi-finished semiconductor devices. To measure the bulk minority carrier lifetime, the interference of surface recombination must be excluded, so a passivation process must be carried out. At present, the commonly used passivation methods for germanium mainly include silicon dioxide passivation, sulfur passivation, chlorine passivation, and hydrogen passivation. [1] . Silicon dioxide is to use magnetron sputtering to use silicon as a target or to pass oxygen into PECVD to obtain a silicon dioxide passivation layer in an oxygen atmosphere; sulfur passivation is to put a germanium single wafer with a c...

AI Technical Summary

Problems solved by technology

Silicon dioxide is to use magnetron sputtering to use silicon as a target or to pass oxygen into PECVD to obtain a silicon dioxide passivation layer in an oxygen atmosphere; sulfur passivation is to put a germanium single wafer with a clean surface into an ammonium sulfide solution Obtain an atomic layer of sulfur atoms and surface germanium atoms with hanging bonds; chlorine passivation is to make chlorine atoms adsorb on the surface of germanium single crystal under the condition that the gas atmosphere of chlorine gas, hydrogen chloride gas and nitrogen gas is greater than atmospheric pressure to achieve the passivation effect. Cause surface etching damage, which is unfavorable to post-processing; the hydrogen passivation method is to put the surface of the germanium single crystal surface with clean surface into the ammonium fluoride solution to form a one-to-one Ge-O single-layer atomic passivation layer, the passivation method Will cause the germanium surface roughness to increase

According to literature reports, the oxide formed on the surface of germanium single crystal in air is difficult to remove. The treatment method is as follows. Cleaning and then adopting other passivation methods for processing, this process is complicated and the efficiency is very low