Investigation of stress and structural damage in H and He implanted Ge using micro-Raman mapping technique on bevelled samples

The results on structural damage in germanium wafers caused by hydrogen and helium implants of typical doses used in Smart Cut (TM) Technology (16 x 10(16) atoms/cm2) are investigated using Raman mapping and spreading resistance profiling techniques. Raman line-mapping measurements were performed up to the depth of similar to 400nm into a Ge substrate (well beyond the limit of visible light penetration depth) using a bevelling technique. From analysis of the GeGe Raman peak it was found that implantation of H and He introduced a different type of stress, tensile and compressive, respectively and significant structural damage with maximum at the projected range. The obtained data shows that hydrogen incorporation in Ge can act as an acceptor. This is undesirable when the hydrogen ion-cut technology is applied to high resistivity Ge. The crystalline structure after implantation is completely recovered when annealed at 600 degrees C for both types of implants. Spreading resistance profiling results reveal that 4-8x1015 acceptors/cm3 remain after 600 degrees C, and these are thought to be because of vacancy related defect clusters. Copyright (C) 2011 John Wiley & Sons, Ltd.