A comparison study of boron emitter passivation by silicon oxide and a PECVD silicon nitride stack

The results show that the optimum passivation is achieved by a stack layer of a thermal SiO2, with a thickness of at least 10 nm, and a SiNX layer with a low refractive index. The chemical composition of SiNX capping layer plays an important role for surface passivation. A more Si-rich SiNX layer show significant degradation in surface passivation of the stack, due to the increase in the density of interface states (Dit) and fixed positive charges (Qtot) at the interface.