Dependence of Luminescence Properties of Bonded Si Wafers on Surface Orientation and Twist Angle.
PL spectra of SOI wafers with buried oxide (BOX) layer were measured after dissolution annealing at 1200°. Depending on mutual orientation of starting base and top wafers different patterns of luminescence bands were observed after annealing. While the small fraction of luminescence clearly originated from dislocation related centers, another intensive band appeared in the range 0.8 – 0.95eV with certain dependence of maximum position on the twist misorientation. TEM investigation confirmed the existence of dislocation net at the interface. On the other hand some peculiarities of PL spectra did not support their relation to dislocations. Though a stepped chemical etch of surface layer confirmed the origin of new band being at the interface too. Therefore a nature of possible defects generated due to dissolution of BOX layer is discussed.
M. Kittler and H. Richter
E.A. Steinman et al., "Dependence of Luminescence Properties of Bonded Si Wafers on Surface Orientation and Twist Angle.", Solid State Phenomena, Vols. 156-158, pp. 555-560, 2010