Abstract: MPI spectrum of Si(CH_3)_4 has been measured in the wavelength range of 410—370 nm. Most of the peaks with strong background were assigned to (2+1) ionization of Si atoms initiated from their ground state 3~3P_J and the first singlet state 3~1D_2. TOF mass spectra showed that Si~+, C_2~+ were the major products at lower laser energy, whereas more ions Si(CH_3)_n~+ (n=1—4), even silicon carbide ion C_3Si~+, appeared at higher energy.

Key words: Multiphoton, Mass detection, Tetramethylsilane