Passivation of silicon surfaces by oxygen radical followed by high pressure Hinf2/infO vapor heat treatments and its application to solar cell fabrication

摘要

We report passivation on the silicon surfaces by combination of oxygen radical and high pressure H2O vapor heat treatment. The top bear surface of 20 Ωcm n-type silicon substrates with the rear surface coated by 100 nm thermally grown SiO2 layers were treated by oxygen radical generated from oxygen plasma via a metal mesh closing the plasma induced by 13.56 MHz radio frequency induction-coupled remote plasma with mixed gases of O2 and Ar at 10 sccm, 1.0 Pa and at a power of 100 W. The samples were subsequently annealed with 1.3×106 Pa H2O vapor heat treatment at 260oC for 3 h. A high effective minority carrier lifetime of 1.1×10−3 s was achieved in the case of 635 nm light illumination on the top surface in the case of the oxygen radical treatment for 3 min. Metal-insulator-semiconductor-type solar cells were formed by formation Al and Au metal strips with a gap length of 17 μm on the passivated surfaces. When airmass 1.5 at 100 mW/cm2 were illuminated on the rear surface with 100 nm thermally grown SiO2 layers, solar cell characteristics were observed by applying volatge between Al and Au elecgtrodes. The open circuit volatge and efficiency were obtained as 0.51 V and 6.4 %.