Silicon Crystal Structure Diamond lattice (Si,Ge,GaAs) Two interpenetrating FCC structures shifted by a/4 in all three directions All atoms in both FCCs ○inside one FCC O from the second lattice covalent bonding (100)Si for devices (111)Si not used-oxide chargestSilicon Crystal Structure Diamond lattice (Si, Ge, GaAs) Two interpenetrating FCC structures shifted by a/4 in all three directions All t i b th FCC All atoms in both FCCs Diamond covalent bonding inside one FCC from the second lattice (100) Si for devices (111) Si not used - oxide charges