Effect of the Laser-Scribing on Spalling of a Single Crystalline Si Using Electrodeposition Assisted Stripping (EAS) Process

Abstract

The single crystalline Si comprises a large proportion of the solar cell overall cost. Lowering its cost is directly related to the cost-reduction in the solar cell. Previously, electrodeposition assisted stripping (EAS) process was employed to obtain a thin Si substrate by applying the high tensile stress on top of Si wafer, which induced the delaminating behavior of thin Si layer. Such a high stress can induce by depositing a Ni layer onto the Si substrate. This stripping phenomenon occurred at the position where the maximum shear stress is applied, which is not on the Si surface but at a certain distance below the Si surface. This research aims to precisely control the initiation point of stripping the thin Si layer by generating intentional micro-cracks on the side of Si wafer. The pre-crack was created by a laser scribing on the side of Si wafer. Also, the process parameters which affected the thickness of stripped Si layer were systematically investigated.