Exceptional silicon surface passivation by an ONO dielectric stack
journal contribution
posted on 2023-05-21, 12:22authored byKho, TC, Fong, K, McIntosh, K, Evan FranklinEvan Franklin, Grant, N, Stocks, M, Phang, SP, Wan, Y, Wang, EC, Vora, K, Ngwe, Z, Blakers, A
Immeasurably low surface recombination of crystalline-silicon wafers is demonstrated with an oxide-nitride-oxide (ONO) corona charged dielectric stack. We detail experimental variations to each layer of the dielectric stack to establish a procedure which provides outstanding passivation properties on textured and planar silicon wafers. We demonstrate surface recombination velocities of < 1 cm/s and surface recombination prefactors of < 1 fA/cm2, and we show that passivation remains stable over a 2-year period when stored in ambient conditions. The effective carrier lifetimes of n-type silicon are found to exceed the commonly accepted intrinsic lifetime limit, and in one case, a lifetime of 170 ms is attained. These high lifetimes indicate that ONO passivation is amongst the best dielectric passivation, and as such, might find applications in high-efficiency silicon solar cells.