Inclusion of dielectric films for surface passivation of buried contact solar cells

Silicon nitride (SiN) has superior reflection properties compared to silicon dioxide (SiO/sub 2/). The use of deposited SiN over a thin oxide, grown during the emitter diffusion, allows the reflection benefits of SiN to be retained while still achieving low surface recombination velocities. This paper shows that for both conventional buried contact and simplified buried contact solar cells, the electrical performance of devices using a SiN/SiO/sub 2/ stack is identical to those using a thick SiO/sub 2/ layer, but the reflection properties are greatly improved. Furthermore, the electrical and reflection properties of LPCVD and PECVD deposited silicon nitride are the same, so the choice of one deposition technique over another depends on how silicon nitride is used in the solar cell process.