FRONT SURFACE PASSIVATION OF N-TYPE HIGH-EFFICIENCY BACK-JUNCTION SILICON SOLAR CELLS USING FRONT SURFACE FIELD

摘要

Front surface passivation of back-junction back-contact n-type Si solar cell structure was analysed.Passivation quality of the phosphorus diffused front surface field, thin thermal oxide and antireflection silicon nitridewas investigated. Surface saturation current densities (J_(0s)) of textured and untextured n~+nn~+ test samples withdifferent n~+ phosphorus diffusion profiles were measured under high and low injection for two sample baseresistivities. Surface saturation current densities determined under high and low injection are in a very goodagreement. For the untextured surfaces the best J_(0s) of 6 fA/cm~2 without the front surface field diffusion and20 fA/cm~2 with shallow lowly doped front surface field were measured. J0s of 31 fA/cm~2 and 27 fA/cm~2 for texturedsamples with and without the front surface field respectively were measured. These low surface saturation currentdensities of textured samples results in V_(oc) limits higher than 705 mV.