From Smart-Cut to Soft-Cut: Mechanisms of Hydrogen Plasma Supported Layer Exfoliation in Silicon

Comparative investigations of silicon layer exfoliation within the Smart-Cut process and its progression at lower H+ implantation doses and subsequent H-plasma exposure (Soft-Cut) were done by µ-Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM) on (100)-oriented Cz Si wafers. Blister formation and evolution at various process temperatures were analyzed to clarify the mechanisms of layer exfoliation for both approaches. On base of the Raman analyses and supporting SEM and AFM measurements of samples prepared under various process temperatures, we identified the V2H6 defect complexes as the precursor of blisters for the Smart-Cut scenario. Under Soft-Cut conditions (100)-oriented platelets created during H-plasma exposure can be identified as the prevailing precursors of blisters.