INTERACTION OF AL WITH OXIDIZED GE SI(001) - A SYNCHROTRON-RADIATION PHOTOELECTRON-SPECTROSCOPY STUDY/

Interaction of aluminum with an oxidized sample of ultrathin layer Ge (7 angstrom) deposited on Si(001) at room temperature [Ge (7 angstrom) /Si(001) RT] is studied employing synchrotron radiation photoelectron spectroscopy. Ge (7 angstrom)/Si(001) RT, on exposure to air, forms Ge suboxides, GeO2 and Si suboxides on the surface. GeO2 is selectively removed completely by rinsing the sample in warm water, and during thi s process a small amount of Si oxides is also formed. Upon depositing Al on this surface, it reacts with oxides of Si and Ge and forms an ov erlayer of Al2O3 on the surface, thereby reducing the oxides to elemen tal Si and Ge. Further, the reaction is activated by an increase in su rface temperature. In the early stages of the reaction, reduction of s uboxides take place in preference to Si02.