Chemistry and kinetics of the interaction of hydrogen atoms with (100)InP surfaces: An in situ real-time ellipsometric study

The interaction of InP surfaces with H atoms is investigated in the afterglow region of H-2 radio-frequency (rf) plasmas by in situ real-time spectroscopic ellipsometry (SE). The effect of the InP surface temperature and the hydrogen plasma exposure time on the native-oxide reduction and phosphorus-depletion processes is studied. The morphology and composition of the InP surface resulting from these two competing processes is well characterized by spectroscopic ellipsometry. Typically complete removal of oxygen is obtained at 230 degrees C after 7 minutes of plasma exposure without damage due to phosphorus depletion. The applicability of real-time ellipsometry to determine precisely the optimum cleaning end point is well demonstrated. The chemistry and kinetics of both oxygen removal and phosphorus depletion are described and the corresponding pseudoactivation energies are derived.