Behaviour of PECVD Silicon Nitride Antireflection and Passivation Layers in Rapid Thermal Firing Through Processes

Rapid Thermal Firing (RTF), i.e. firing of printed contacts by Rapid Thermal Processing, represents a promising alternative compared to firing in infrared heated conveyor belt furnaces. In this work the influence of RTF on the properties of PECVD silicon nitride antireflective and passivation layers deposited from SiH4, N2, and H2 is investigated. Based on ellipsometry measurements, no significant change in the optical properties of silicon nitride antireflective layers due to the RTF process is observed. High surface passivation quality can be maintained for SiNx antireflective layers after RTF. Fourier transformed infrared absorption measurements reveal a strong dependence of the surface passivation quality on the Si H bonding density. Internal quantum efficiency measurements on multicrystalline silicon solar cells show that an effective bulk passivation from the silicon nitride layers can be obtained during a firing through process sequence when RTF is used for conta ct formation.