Cold ion-cutting of hydrogen implanted Si

The strength of the H-implanted layer has been measured in <1 0 0>, <1 1 1> and <1 1 0> oriented Si wafers using the crack opening method. The required annealing temperature for mechanical layer transfer increases in the order <1 0 0>, <1 1 1> and <1 1 0>. The damage induced by the implantation has been studied by Rutherford backscattering in the channeling mode (RBS/C). The same methods have been used to investigate the influence of boron and arsenic doping on the mechanical exfoliation. Boron doping reduces the strength of the H-implanted layer thereby enabling mechanical layer transfer at temperatures below 200 °C. We found that the exfoliation takes place closer to the wafer surface in highly boron doped Si as compared to the undoped Si. The RBS damage peak also appears to move closer to the surface when the boron concentration of the H-implanted layer is >1019 cm-3. No lowering of the exfoliation temperature was observed for compensated and arsenic doped Si layers. We suggest that the lowering of the exfoliation temperature with increasing boron doping is related to Si H bonds associated with the neutralization of shallow acceptors by hydrogen.