An electron-multiplying "Micromegas" grid made in silicon wafer post-processing technology

A technology for manufacturing an aluminium grid onto a silicon wafer has been developed. The grid is fixed parallel and precisely to the wafer (anode) surface at a distance of 50 \mum by means of insulating pillars. When some 400 V are applied between the grid and (anode) wafer, gas multiplication occurs : primary electrons from the drift space above the grid enter the holes and cause electron avalanches in the high-field region between the grid and the anode. Production and operational characteristics of the device are described. With this newly developed technology, CMOS (pixel) readout chips can be covered with a gas multiplication grid. Such a chip forms, together with the grid, an integrated device which can be applied as readout in a wide field of gaseous detectors.