ELECTRON-IRRADIATION EFFECTS ON DIGERMANE ADSORBED ON SI(100) SURFACES

The effects of electron-beam irradiation on digermane adsorbed on Si(1 00) at 120 K have been investigated by temperature programmed desorpti on (TPD), Digermane adsorbed on clean Si(100) at low exposures exhibit s a single H-2 TPD peak at 800 K, which originates from the silicon mo nohydride state on the Si(100) surface. At higher digermane exposures, a new peak appears between 550 and 570 K, and the 800 K peak shifts t o lower temperatures. The 570 K peak is believed to originate from sur face germanium hydride species. At the highest digermane exposures, a molecular desorption peak appears at approximately 140 K. Electron exp osure of Si(100) dosed heavily with digermane causes the molecular TPD peak at 140 K to decrease in intensity and broaden, with a concomitan t increase in TPD peak intensity at 570 K, indicating that the electro n beam dissociates physisorbed digermane species via deposition of GeH x species onto the Si(100) surface.