Microstructure evolution of hydrogen-implanted silicon during the annealing process

Mechanics of Smart-Cut® technology

“…Taking U H ¼ 60 KeV, for instance, Eq. (12) leads to d H ¼ 540 nm, which agrees well with observations of Wang et al (2003). Therefore, the implantation energy of hydrogen ions necessary for a desired structure can be easily estimated from the linear relationship in Eq.…”

“…3(a). Wang et al (2003) observed that most defects in the damaged layer are platelet-like, parallel to the wafer surface, about 0.3-0.6 nm wide and 5-20 nm long. These microcracks are filled with hydrogen molecules (H 2 ) and are coated with atomic hydrogen captured at broken and dangled Si bonds at the pore surface and at the crack tip (Weldon et al, 1997;Kozlovskii et al, 2000).…”

“…The implantation process pushes more and more hydrogen ions into the voids, causing the increase of internal pressure. The trapped hydrogen atoms diffuse and agglomerate near the peak implantation region during thermal annealing, forming microvoids filled with H 2 molecules (Weldon et al, 1997;Wang et al, 2003). The high pressure inside the microcavities, which is magnified significantly during thermal splitting, is the driving force for nucleation and expansion of defects.…”

“…Experimental studies have shown that most hydrogen ions are concentrated in a thin layer (about 100-200 nm thickness) which, depending on the energy of the implanted hydrogen ion beam, is several hundreds nanometers or a few microns below the surface of an implanted wafer (Bedell and Lanford, 2001;Wang et al, 2003). It can easily be shown from energy balance that if the frictional resistance is assumed to be constant during the penetration of a hydrogen ion into single-crystal silicon, the penetration depth of the hydrogen ion, d H ( Fig.…”

“…The effect of splitting of a wafer along the damaged (or porous) layer is based on the phenomenon of pore coarsening (i.e., growth and coalescence of microvoids), which occurs anisotropically and mainly parallel to the surface of the wafer (Kozlovskii et al, 2000;Wang et al, 2003). Growth and coalescence of microvoids leads to formation of microcracks (Feng and Yu, 2002), which are basically aligned in the same direction, as shown in Fig.…”