Arrangement for the examination of ions, atoms and molecules in gases and liquids

摘要

An arrangement is described for examining ions, atoms and molecules in gases and liquids using a field-effect semiconductor component. In known gas-sensitive field-effect transistors, the shifting of the threshold voltage by the particles to be detected is used for the measurement. Since the threshold voltage depends strongly on the position of the working point, the measurement is falsified by working-point instabilities. The new arrangement draws, for the measurement, on the change in the amplification factor by the particles to be detected. The gate electrode is composed of partial electrodes (4) which have no conducting connection with the gate contact (3). Under the influence of the particles to be measured, an increasing number of partial electrodes (4) is connected to the gate contact (3), which increases the effective area of the gate electrode and the amplification factor of the arrangement. <IMAGE>