As manufacturing technology has improved over the past few years, it is inevitable that the size of components to be manufactured has been affected, and the desire to reduce the size of such components is the driving force behind the move towards micro-and nanotechnology. One of the problems is the electrode breakdown at electrode separations for less than a millimetre separation. At large separation, the behaviour of the electrodes has been widely studied and is reasonably well understood. However, some fundamental problems have not been properly addressed such as maximum safe operating voltages and critical dimensions required at the small separations between the different types of materials. A systematic study of electrical breakdown at sub-millimetre separations using materials commonly used in the fabrication of microdevices is being undertaken. Specimens for examination at electrode separations from 500 nm to 25 µm have been made with different electrode configurations, such as flat to flat and flat to point.

For efficient operation, micromotors and microactuators, such as those employed in microsystems, are required to operate with high electric fields at electrode separations of the order of micrometres. An apparatus was built to accurately measure the breakdown voltage for electrode spacings as low as 0. 5~. Breakdown voltage measurements in air and nitrogen are presented and discussed for the gap range 0.5 to 1 5~. Energy dispersive analysis of X-rays (EDAX) confirms the transfer of material from cathode to anode and vice V L ' I :~ during the breakdown mechanism. The Paschen law has been confirmed not to be applicable at gap settings of less than 4 p. The shape of the curve and the breakdown voltage values are found to be the same for different gases and different high pressures up to 4 p separation. Below this value, an analytical explanation of the breakdown voltage based on quantum tunnelling of electrons is obtained in terms of electrical field enhancement at microprotrusions and the work function of the electrode material.

At large separations, the behaviour of electrodes has been widely studied and is reasonably well understood. However, some fundamental problems have not been properly addressed such as maximum safe operating voltages and critical dimensions required at small separations between different types of materials. A systematic study of electrical breakdown at sub-millimetre separations using materials commonly used in the fabrication of microdevices has been undertaken. Specimens for examination at electrode separations from 500 nm to 25 m have been made with different electrode configurations, such as flat to flat, flat to point and point to point. All the tests were made in air and at differing pressures.

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