Monocrystalline silicon passivation contact structure and preparation method thereof

Abstract

The invention discloses a monocrystalline silicon passivation contact structure and a preparation method thereof. The monocrystalline silicon passivation contact structure comprises a monocrystallinesilicon wafer, n layers of HfOx and HfNy are alternately deposited on the front and back surfaces of the monocrystalline silicon wafer, and n is equal to 5-20. The thickness of each layer of HfOx or HfNy is 3nm, wherein the layer closest to the monocrystalline silicon wafer is the first layer, namely HfOx1 and HfNy1, and the layer farthest from the monocrystalline silicon wafer is the n-th layer,namely HfOxn and HfNyn; 2.0 > x1 > x2 >... > x9 > xn > 1.0, and 1.33 > y1 > y2 >... > y9 > yn > 0.67. An HfOx/HfNy multilayer film with gradually changed components is deposited by adopting a reactivemagnetron sputtering method, full-surface passivation and selective contact of monocrystalline silicon are realized, the defects of a tunneling oxide layer passivation contact technology can be overcome, and the monocrystalline silicon passivation contact structure has the advantages of no use of dangerous gas (silane, phosphorane or borane), high deposition speed, low cost and the like.

Description

technical field [0001] The invention belongs to the field of crystalline silicon solar cells, and relates to a monocrystalline silicon passivation contact structure of a hafnium oxide / hafnium nitride multilayer thin film with gradually changing composition, and a preparation method thereof. Background technique [0002] As the minority carrier lifetime of monocrystalline silicon wafers is greatly improved and the thickness is continuously reduced, how to reduce the recombination of carriers on the surface of silicon wafers is the key to further improving the efficiency of crystalline silicon solar cells. Surface passivation can be divided into chemical passivation and field effect passivation. Chemical passivation is usually used to combine the dielectric film with the dangling bonds (uncoordinated silicon atoms) on the silicon surface to reduce the defect density at the interface. . Field effect passivation is to obtain a built-in electric field by doping down the interfac...

AI Technical Summary

Problems solved by technology

Since the silicon dioxide used as the tunneling layer is usually only 1.0-2.0nm, the heavily doped impurities in the polysilicon will diffuse into the silicon dioxide in the subsequent annealing process of the crystalline silicon cell, resulting in the passivation effect of the silicon dioxide on the crystalline silicon. become worse

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