Group II Cubic Fluorides as Dielectrics for 3-D Integration and GaAs-BasedOptoelectronic Structures

摘要

The epitaxial growth of CaxSr1-xF2/GaAs(100) and GaAs/CaxSr1-xF2(l00) isinvestigated. Optimum growth temperature of 5300C, growth rate of 1A /sec and composition x=0.47 lead to very high crystallinity layers of mixed fluorides on GaAs. The growth of GaA.s/Ca0.47Sr0.53F2(100), rendered much more difficult by the morphology and faceting of the insulating surface, is substantially improved by modifying the fluoride surface by electron irradiation prior to GaAs growth, and by a two-step growth sequence where the interface GaAs is grown at low temperature (300 deg C). Finally, the patterning of the fluoride layer is performed by e-beam exposure. Features as small as 1 micron are drawn and developed on a 2060 deg thick CaF2 layer, opening the possibility of using the fluorides for wave-guides or re-growth of small III-V features. Semiconductor/insulator interfaces; GaAs; Ca x Sr 1-x F2; molecular beam epitaxy.