DICHLOROSILANE EFFECTS ON LOW-TEMPERATURE SELECTIVE SILICON EPITAXY

Low-temperature selective silicon epitaxial growth using a dichlorosilane-hydrogen mixture in a low-pressure chemical vapor deposition hot-wall reactor has been studied. A simple HF vapor treatment effectively removes surface oxides and passivates the Si surface prior to reactor loading. The addition of a small concentration of dichlorosilane to the H-2 ambient during the prebake at a temperature of 900-degrees-C improves selective epitaxial quality both by maintaining an oxide-free surface, and by suppressing undercut of oxide-covered regions. With these process improvement defect-free, selectively overgrown Si epitaxial layers are achieved at deposition temperatures between 800 and 850-degrees-C.