CHEMICAL VAPOR DEPOSITION OF THIN FILM MATERIALS FOR ...

the existence of both physisorbed and small amount of chemisorbed TDMAH molecules on the
surface.
Fig. 26. Change of ratio of peak 2770 cm -1 to the whole C-H stretching area in the period of adsorption and
desorption at different substrate temperatures.
The profile of Si-H bonds changing on the ATR silicon crystal surface in the period of
TDMAH adsorption and desorption at different crystal temperatures is showed in Fig.27. As one
can see, at 100˚C, there is almost no change of surface Si-H bonds in the adsorption and
desorption process. Starting from 150˚C, the introduction of TDMAH induced apparent
subtraction of surface Si-H bonds and after stopping TDMAH flow the surface Si-H bonds kept
in a stable level. Sufficient thermal energy is achieved above 150˚C for the reaction between
TDMAH and Si-H bonds to happen. The stable Si-H bonds after TDMAH introduction indicates
that the thermal energy itself can not break these bonds. The reaction of surface Si-H bonds with
the thermally activated (or decomposed) TDMAH molecules is the main way for surface bonds
subtraction.[149]
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