Shalom

Magnesium Aluminate  (MgAl₂O₄  or spinel) single crystals are widely used for bulk acoustic wave and microwave devices and fast IC epitaxial substrates. It is also found that MgAl₂O₄ is a good substrate for III-V nitrides device. Spinel (MgAl₂O₄) is one candidate for such GaN LDs substrate. The crystallographic structure of MgAl₂O₄ is a spinel type (Fd3m), and its lattice constant is 8.083 A. MgAl₂O₄ is a relatively low-cost substrate material, which has been successfully applied to the growth of high quality GaN films. MgAl₂O₄ is cleaved on the (100) plane. GaN LD cavities have been obtained by simply cleaving MgAl₂O₄ substrates along the (100) direction, which will also work well for ZnO. MgAl₂O₄ crystal is very difficult to grow, due to the difficulty in maintaining a single phase structure.