CHARACTERIZATION OF SINGLE-CRYSTALLINE AL FILMS GROWN ON SI(111)

Single-crystalline Al films have been grown by molecular beam epitaxy on a (7x7) reconstructed Si(111) surface at 50 degrees C. The 100 nm t hick Al films were extensively characterized by X-ray diffraction, tra nsmission electron diffraction and microscopy, SIMS, and RES in combin ation with ion channeling. The orientational relationship found was Al (111) parallel to Si(111) and Al[<1 (1)over bar 0>] parallel to SiC[<1 (1)over bar 0>]. The him is single-crystalline over the entire 4 '' S i wafer. TED and TEM showed that the lattice mismatch of 25.3% at room temperature is accommodated at the interface by alignment of every th ree Si atoms to four Al atoms. Annealing of the film at 400 degrees C for 30 min led to a reduction of defects in the film and an increase a t the interface. Furthermore, it increased the Si concentration in the Al film slightly. We regard this deposition method as the most approp riate one among the various techniques for epitaxial growth of Al on S i explored so far.