The effects of synchrotron x-rays on the local structure and the recrystallization of ion damaged Si

We have studied the effects of intense x-ray irradiation on the structure of crystalline Si amorphized by energetic ions and the subsequent solid phase epitaxial regrowth of the amorphous layers. We found that in the amorphized Si layers, although the ion dose is well above the amorphization threshold (as measured by Rutherford backscattering), small crystallites are still present. The absorption of x-rays by the Si atoms provides enough energy to disperse the small crystallites in the amorphous Si, reducing the number of interfacial defects as well as locally rearranging the atoms to form a homogeneously amorphous layer with close to four-fold coordinated environment. This rearrangement in local structure of the α-Si results in a nearly defect-free crystal after solid phase epitaxy.