HYDROGEN DESORPTION PROCESS OF SI(100) PH3

Adsorption of PH3 onto Si(100) and hydrogen desorption therefrom at va rious adsorption temperatures T-a have been investigated by the temper ature-programmed-desorption (TPD) method which includes measurements o n repeatedly adsorbed surfaces to obtain the surface phosphorus covera ge. The TPD peak showed a shift toward higher temperatures for T-a abo ve 400 degrees C, which can be correlated to the onset of the hydrogen desorption and a resultant concentrated adsorption of the phosphorus atoms during exposure. A support for this correlation is given by furt her analysis of the TPD line shape, which clarified that surface phosp horus restricts hydrogen desorption both by suppressing hydrogen assoc iation and by increasing the desorption energy. (C) 1995 American Inst itute of Physics.