Random Albacksurfacefield(BSF)p-typeSisolarcellsarepresented,whereastackofAl2O3 and SiNx is
used asrearsurfacepassivationlayercontainingblisters.Itisshownthatnoadditionalcontactopening
step isneeded,sinceduringco-firinglocalAlBSFsareinducedatthelocationoftheseblisters.Thebest
fill factorsandshortcircuitcurrentsareobtainedinthecaseof(i)ahydrophobicpre-passivation
cleaning,sinceitleadstoasmalldensityoflargerblisters,and(ii)10nmofAl2O3, wheretheblistering
size stillincreasesduringfiringthankstoadditionalout-gassing.Thereisanapparentgainin Jscand
Voc of,respectively,1.3mA/cm2 and 5mVforthebestrandomAlBSFcellscomparedtofullAlBSF
referencecells,becauseofbetterrearinternalreflectionandrearsurfacepassivation.