Sapphire crystallographic planes

B2.1 Sapphire substrates for growth of GaN and related compounds TABLE 3 Crystallographic planes in sapphire. 

These tests were performed using an Instron Model 8561 (single screw) machine in air and the furnace was adapted to perform four-point bend tests. The rates indicated in Fig. 2.3 relate to crosshead displacement. Figure 2.4 shows the resolved shear stress at yield for the specimens tested ate = 4.2 x 10 s above Tc at the indicated orientations. The mechanism for slip is dislocation glide, which explains the orientation dependence of yield, as seen in Fig. 2.4. Thus, the BDT temperature, Tc, of the sapphire (AI2O3) varies not only with the strain rate, but also with the crystallographic orientation of the fracture plane. 

Sapphire C substrates are selected in order to fabricate highly oriented LiNbOs thin films, because the c-plane of LiNbOs has the good crystallographic matching with c-plane of a-AlsOs. Figure 17-2 shows the XRD profile of the LiNbOs thin film from... 

Erom a crystallographic point of view, (1120) a-plane SiC is a better substrate for epitaxial growth of a-plane GaN than the r-plane sapphire. First, the layer and substrate have identical crystal orientation and the epitaxial relationships... 

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