MASS-SPECTROMETRY STUDY OF THE GAS-PHASE REACTIONS IN THE CVD OF SI AND IN-SITU-PHOSPHORUS DOPED SI IN ORDER TO EXPLAIN THE DIFFERENT GROWTH-RATES

The experiments have been carried out in a vertical impinging jet type reactor in order to have a kinetically controlled growth. Two types o f heating modes were used : hot wall reactor (HWR) and cold wall react or (CWR). The gas phase compositions have been determined by coupling the reactor to a quadrupole mass spectrometer (QMS), while the growth rates were measured versus temperature and phosphine to disilane molar ratio in order to determine the species responsible for the deposits. Disilane draws a decrease in the inhibition of the growth rate which is 4 times less than in the case of monosilane as starting product. In contrast, phosphorus incorporation, which is in the range 1,5.10(19)- 8.10(20) atom cm-3, keeps the same order of magnitude.