ROLE OF THE -SIH3 FUNCTIONAL-GROUP IN SILANE ADSORPTION AND DISSOCIATION ON SI(100)

The adsorption and reaction behavior of methylsilane (CH3SiH3) and dis ilane (Si2H6) On Si(100) single crystals has been studied using temper ature-programmed desorption (TPD) and Auger electron spectroscopy (AES ). It was found that CH3SiH3 and Si2H6 molecules have similar adsorpti on behavior while ethane (C2H6) does not stick on Si(100) at 90 K. The se results indicate that -SiH3 is the key functional group involved in silane adsorption. The adsorption coverage of CH3SiH3 at 90 K was fou nd to be about twice as large as that at 300 K, indicating that methyl silane adsorbs dissociatively on Si(100) at 300 K with the breaking of the Si-C bond, producing enhanced dangling bond site blockage compare d to the undissociated chemisorbed molecule. Based on the results, pen tacoordinate silicon in -SiH3 groups is postulated to be involved in t he nondissociative chemisorption and in the S(N)2 dissociative reactio n of CH3SiH3 on dangling bond sites on Si(100).