Field emission diode for protecting electronic circuits from overvoltages - with single crystal silicon@ anode substrate and field emission cathode bridge

摘要

Field-emission diode has a single crystal Si substrate and is electrically insulated from a field-emission cathode, with the following features: 1) the substrate (2) forms the anode and has a recess (4); 2) the field-emission cathode (6) is formed as an unsupported bridge (8) mounted on distance pieces (10) and provided on its surface facing the substrate with a projection (12) which is inserted into the recess in the substrate. The device is mfd. as follows a) a single crystal Si substrate is provided with an oxide layer mask on one of its (100) surfaces; b) at least one window is opened in the mask, the side edges of which are parallel to the tracks of the (110) faces of the Si crystal on its (100) face; c) a recess is formed by anisotropic etching inside the window, bounded by the (111) faces of the Si crystal; (d) the mask is removed and the substrate surface is provided with an insulating layer; e) a cathode layer is deposited on the insulating layer and is structured in the region of the recess; and f) the insulating layer is removed underneath the cathode layer by etching until the cathode layer region forms an unsupported bridge over the recess. USE/ADVANTAGE - The device is used in vacuum micro-electronic applications as a voltage-limiting component to protect electronic circuits. The device rapidly dissipates overvoltages above a predetermined threshold level. It is insensitive to temp. and to magnetic radiation.