No abstract

No abstract

Doping layers commonly have but one function: supplying the dopants to form a doped region within a substrate. This work presents B doping layers/stacks, which at the same time supply dopant atoms, passivate the B-doped crystalline Si surface sufficiently well (j 0E < 50 fA/cm 2 ), and show optical properties suitable for anti-reflective coating. Furthermore, these boron silicate glasses can act as a barrier against parasitic P in-diffusion during a co-diffusion step. The boron emitters diffused from the inductively coupled plasma plasma-enhanced chemical vapor-deposited B containing SiO x layers are investigated and optimized concerning passivation quality and contact properties for high-efficiency n-type solar Si cell designs. It is shown that even 10 nm thin SiO x :B films already allow for suitable emitter sheet resistance for screen-printed contacts. Furthermore, SiO x :B layers presented here allow for iV OC values of 675 mV and contact resistivity of 1 mXcm 2 for commercial Ag instead of Ag/Al pastes on the diffused boron emitter passivated with the SiO x :B layer supporting the contact formation. All of these properties can be achieved within one single B doping layer/stack. V C 2015 AIP Publishing LLC. [http://dx

No abstract

In the production of n‐type Si solar cells, B diffusion is commonly applied to form the p+ emitter. Up to now, Ag screen‐printing pastes, generally used to contact P emitters, had been incapable of reliably contact B emitters. Therefore, a small amount of Al is generally added to Ag pastes to allow for reasonable contact resistances. The addition of Al, however, results in deep metal spikes growing into the Si surface that can penetrate the emitter. Losses in open‐circuit voltage are attributed to these deep metal spikes. In this investigation we demonstrate, that state‐of‐the‐art Al‐free Ag screen‐printing pastes are capable to contact BBr3‐based B emitters covered with different dielectric layers and reach specific contact resistances <1 mΩ cm2. Bifacial n‐type solar cells with Al‐free Ag pastes on both sides show efficiencies of up to 18.3% and series resistances <0.5 Ω cm2. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)