Hydrogen desorption process of Si(100)/PH3

Adsorption of PH3 onto Si(100) and hydrogen desorption therefrom at various adsorption temperatures Ta have been investigated by the temperature-programmed-desorption (TPD) method, which includes measurements on repeatedly adsorbed surfaces to obtain the surface phosphorus coverage. The TPD peak showed a shift toward higher temperatures for Ta above 400 °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 further analysis of the TPD line shape, which clarified that surface phosphorus restricts hydrogen desorption both by suppressing hydrogen association and by increasing the desorption energy.