Real time observation of fast processes occurring in a time window of a few milliseconds to a few minutes have been always difficult to observe by x-ray excited photoemission (XPS) studies under laboratory conditions. However the demand to understand the chemistry of surface processes e.g. during heating processes, electro migration and diffusion is of high relevance in various research fields.

 

In this contribution we will report on first results of a new multi-anode detector concept with 128 individual anodes, preamplifiers and counters. It has the capability to allow for quantitative XPS studies on fast time scales with good signal to noise ratio excited with a monochromated Al Ka laboratory source. The detector can be operated in snapshot XPS mode. This mode allows recording an energy window in the spectrum versus time with high repetition-rates and good energy resolution, e.g. a 15 eV detectable energy window with an approximate energy resolution of 0.5 eV.

 

As an early application we report on results of removing an in-situ grown SiO2layer on a Si substrate. The measurement was made during a sample temperature ramp from 600 to 900 degree Celsius within a time frame of one hour. The target of the experiment was to analyze the time window in which the oxide was removed.

 

Snapshot spectra have been recorded with an acquisition time of 0.5 seconds per spectrum to follow the evolution of the subcomponents Si4+ to Si0during the heating process of the Silicon. The snapshot series with >5000 spectra shows the evolution of the peak versus time. The complete removal of the oxide occurred at a very small temperature window around 850°C. A closer look into the data revealed that the removal of the oxide from the silicon took place in about 2.5 minutes. Within this transition time 300 spectra have been recorded.