Influence of grain orientation on contact resistance at higher emitter resistances, investigated for alkaline and acid saw damage removal

The relation between grain orientation and contact resistance was investigated for alkaline and acid saw damage removal using the Corescan and optical microscopy. For alkaline etched cells, it was found that grains oriented near <100> are badly contacted, while other orientations are well contacted. A sheet resistance scan on the emitter of a neighbour wafer suggests a relation between <100> orientation and increased sheet resistance, but whether this explains the bad contact is far from clear yet. For acid etched cells, the contact resistance was found to be low for all orientations. This means that acid etching does not reduce only reflectance losses, but contact resistance losses as well.