The invention provides a method and
system for cleaning the surface of a
silicon substrate, and the method comprises the steps: firstly forming an H-Si
passivation layer on the surface of Si through H free radicals, and then introducing NH3 to enable the H-Si
passivation layer to be selectively adsorbed on the surface of SiO2; after residual gas-phase substances are purged and removed through
inert gas,
fluorine free radicals (F *) generated by
plasma dissociation of NF3 are introduced, the
fluorine free radicals react with the pre-adsorbed NH3 on an interface,
solid ammonium salt (NH4) 2SiF6 is generated in situ, and then the
solid ammonium salt (NH4) 2SiF6 is removed through
thermal decomposition. According to the method, an H-Si
passivation layer is formed on the Si surface through H free radicals, and a gas-
phase reaction path of NF3 and NH3 is blocked by means of a physical isolation mechanism. According to the method, indifference
etching of
fluorine free radicals on the
silicon substrate is eliminated, substrate damage caused by a traditional
mixed mode is avoided, the atomic-scale flatness of the
silicon surface is kept, meanwhile, by optimizing heat conduction and
deuterium bond repairing, the slippage defect induced by thermal stress is effectively restrained, the interface
state density is reduced, and the interface
electrical performance is improved.