A One - Chip Solution of a Mass Spectrometer

Abstract

A fully integrated mass spectrometer on one chip with a time of flight (TOF) mass filter is presented. This miniaturized mass spectrometer (MMS) is predestinated for mobile measurements, portable applications as well as continuous process monitoring. The MMS uses a microwave plasma electron source providing a high density electron beam for electron impact ionization. The integrated ion optics extracts and focuses the ion beam into the mass separator, where short ion pulses diverge based on their mass-to-charge ratio. The implemented energy filter increases the resolution of the MMS by filtering the ions according to their energy before these are recorded by the detector. MEMS technology allows all critical structures to be fabricated by a one mask anisotropic deep silicon etch. Hence, the MMS is very cost efficient due to its mass producibility. Its small size (5times10 mm) reduces the vacuum requirements by a few orders of magnitude, so that a one stage pumping system achieves the necessary vacuum reducing the overall size of the system. Mass spectra of different gas compositions measured with the MMS are presented.