Dissociative adsorption of monomethylsilane on Si(100) as revealed by comparative temperature-programmed desorption studies on H/, C2H2/, and MMS/Si(100)

Dissociative adsorption of monomethylsilane (MMS), a promising precursor ga s for low-temperature SiC, has been investigated on Si(100) by using temper ature-programmed desorption (TPD) method after its comparison with H/ and C 2H2/Si(100) surfaces. For both MMS/ and C2H2/Si(100), the beta(1) peak from SiH species showed a shift to higher temperatures in the presence of surfa ce C atoms, while two new peaks appeared separately for the two gases: gamm a peak (similar to 640 degrees C) for the C2H2/ and delta peak (similar to 870 degrees C) for the MMS/Si(100). The gamma peak is suggested to be from hydrogen desorption from SiH species at which a C atom is inserted to its b ackbond. The delta peak is related to desorption from surface CH, species. The absence of the gamma peak on MMS/Si(100) suggests absence of atomic exc hange between surface C and substrate Si atoms on its adsorption. (C) 2000 Elsevier Science B.V. All rights reserved.