SURFACE-TREATMENT EFFECTS ON MICROSCOPIC SI SURFACE-STRUCTURE AND SI-SIO2 INTERFACE STATE

Surface treatment effects on the micro-morphology of Si(111) surface a nd interface state density (D-it) of the Si(111)/SiO2 prepared by phot o-induced chemical vapor deposition (photo-CVD) have been investigated by atomic force microscopy (AFM) and deep level transient spectroscop y (DLTS) method. Well-ordered atomic steps and flat terraces are clear ly observed on the Si(111) surfaces treated in NH4F solution or in boi led deionized water. For these atomically flat substrates, the values of D-it become less than that of the sample treated by 1%HF solution. In addition, F-2 treatment effects ts before SiO2 growth have also bee n examined by AFM, DLTS method and photo I-V method, The value of D-it is decreased at the substrate temperature below 250 degrees C with mi nimal value at about 200 degrees C, Electron scattering length near th e interface is not changed by the F-2 treatment.