Ion Implantation and Synthesis of Materials - Studium

11.4 The Mechanisms Behind the Ion-Cut Process 151a number of techniques. Figure 11.7 shows a high resolution scanning electronmicroscopy (SEM) cross-section image of the exfoliated layer. The image showsthe roughness of the surface, where the Ion-Cut occurred, to be quite small. Alsovisible is the 75 nm thick silicon oxide layer beneath the bond interface. The largearea analysis possible with SEM reveals a uniform thickness of the exfoliatedlayer and consequently a smooth cut of the H-implanted silicon crystal. The SEMdeterminedthickness of the exfoliated layer is measured to be 1.42 µm. A surfaceheight analysis using atomic force microscopy (AFM) shows the transferred layerto be 1.40 µm thick. Examination of the exfoliated layer by means of cross-sectiontransmission electron microscopy (XTEM) measures the thickness of thetransferred layer as 1.42 µm.Figure 11.8 combines all the data mentioned above. The H concentration and Silattice damage distributions are superimposed. The dashed vertical lines in thefigure represent the range in the Ion-Cut location determined by XSEM, AFM andXTEM. This data clearly shows that the Ion-Cut occurs at the region of highestimplantation damage rather than at the H concentration peak. To understand whythe Ion-Cut depth is correlated with the ion implantation damage requires a closerexamination of the nature of the damage.4Hydrogen concentration (at %)32101.0 1.2 1.4 1.6 1.8 2.0Depth (µm)Fig. 11.6. The H concentration depth distribution obtained from an ERD analysis on thesilicon sample implanted with 175 keV protons to a dose of 5 × 10 16 H cm 2