Plasma–silicone interaction during a-Si:H deposition on solar cell wafers bonded to glass

Heterojunction Interdigitated Back-Contact Solar Cells Fabricated on Wafer Bonded to Glass

“…The wafers are manually bonded on the glass and the wafer/silicone/glass stack is cured at a temperature of 200 • C for 1 h in a vacuum. This additional curing is performed to avoid silicone contamination of the plasma chamber during PECVD deposition [9], [21]. The samples are then left in the vacuum overnight in order to remove air bubbles that are created during the manual bonding.…”

Kerfless layer-transfer of thin epitaxial silicon foils using novel multiple layer porous silicon stacks with near 100% detachment yield and large minority carrier diffusion lengths

“…The residual porous silicon belonging to the annealed LP-TL must be removed using a silicon etchant that does not react strongly with the silicone. Moreover, silicone should not be directly exposed to the plasma during amorphous silicon deposition, because it will lead to very poor surface passivation [15][16][17]. In order to minimize the problems associated with silicone, a shielded configuration (i.e.…”

Role of O2radicals on silicone plasma treatments for a-Si:H surface passivation of PV wafers bonded to glass

“…This double thermal treatment is developed in Ref. and is identical to the one performed on bonded wafers. Afterwards, the samples are exposed either to an O 2 plasma or an Ar plasma performed in a reactive ion etching (RIE) reactor for a time between 10 s and 5 min and according to the following process parameters: input power density ( P input ) of 636 mW/cm 2 , pressure of 0.1 Torr, and gas flow of 100 sccm.…”

“…As a consequence, the silicone and glass may introduce additional constraints on these process steps and compromise device performances. Specifically, the presence of silicone during the step of a‐Si:H surface passivation strongly degrades the passivation quality . For this reason, different solutions have been developed to limit the influence of silicone on the a‐Si:H passivation process, which include changes in the wafers/silicone/glass geometry , introduction of additional outgassing steps , and silicone oxidation by oxygen (O 2 ) plasma .…”

“…Among these three solutions, silicone oxidation by O 2 plasma is considered the one with the highest potential. This is mainly because such method is proven to limit the silicone influence on the passivation process for different silicones , while the efficacy of the two other methods still depends on the bonding material and sample geometry . The limited influence of the oxidized silicone on the passivation process is explained by the modifications induced on the silicone surface by the O 2 plasma.…”