Surface passivation by rehydrogenation of silicon-nitride-coated silicon wafers

A silicon wafer with a silicon nitride layer deposited by low pressure chemical vapour deposition may be subjected to high-temperature treatments without adversely affecting the electronic properties of the silicon on the condition that a thin oxide is present under the nitride. After high-temperature treatments there is an apparent degradation in effective lifetime, probably due to a loss of hydrogen from the silicon/oxide interface. Effective lifetimes can be completely recovered by thermal treatment in a hydrogen-containing ambient. This work has useful applications for solar cells as many of the properties of these nitrides can be used to advantage.