Impact of ammonia pretreatment of the silicon surface prior to the deposition of silicon nitride layer by pecvd

Erwann Fourmond (1) , Julien Dupuis (1) , F. Marcq (1) , C. Dubois (2) , Mustapha Lemiti (1)

1 INL - PV - INL - Photovoltaïque
2 INL - DE - INL - Dispositifs Electroniques

PECVD Hydrogenated silicon nitride is widely used for Silicon solar cell as antireflection coating and passivation layer. This kind of layer exhibits a high hydrogen content, which is likely to diffuse during thermal step, leading to a chemical change of within the layer and at the interface. Thus a problem of adherence of silicon nitride, called blistering, may occur after rapid thermal anneal. NH3 or N2 plasma pretreatment has been here applied before deposition step for standard and Si-rich silicon nitride. Both treatments have successfully prevented surface to blister. In term of passivation, this pretreatment degrades the surface velocity recombination after deposition, but high life- times are recovered after anneal, particularly for NH3. The treatment is efficient starting from 30s. Ammonia plasma cleans the surface of the silicon by removing carbon, but not does N2. No nitridation of the surface is observed due to this pretreatment, and the native silicon oxide is not removed.

Mots clés: PECVD; Silicon-Nitride; Passivation

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Erwann Fourmond, Julien Dupuis, F. Marcq, C. Dubois, Mustapha Lemiti. Impact of ammonia pretreatment of the silicon surface prior to the deposition of silicon nitride layer by pecvd. 23rd European Photovoltaic Solar Energy Conference and Exhibition, Sep 2008, Valencia, Spain. pp.1629-1632. ⟨hal-00546519⟩