| 摘要 |
1,201,718. Semi-conductor devices. TELEFUNKEN PATENTVERWERTUNGS G.m.b.H. 19 June, 1968 [22 June, 1967; 24 Feb., 1968], No. 29276/68. Heading H1K. The metal rectifying contact 8 of a Schottky diode is flared out over that part 9 near the surface of the semi-conductor diode body 1 to produce a marginal portion which terminates abruptly at its outermost end and has a thickness which decreases towards the outside. A diode with such a contact has a high inverse breakdown current with a high reverse voltage. The contact is manufactured by initially covering the diode body, which may comprise an N- type epitaxial layer on an N+ type silicon substrate, with a layer 4 of silicon dioxide and a further layer 5 of silicon monoxide, coating the layer 5 with a photo-lacquer except for those parts where the metal contact is to be, and etching with buffered hydrofluoric acid when the silicon monoxide layer 5 will be removed over the unlacquered area and the silicon dioxide layer 4 will also be removed at a faster rate to produce an aperture which widens out towards the surface of the body; the metal contact is then applied by vapour deposition and will be flared out because of the shape of the aperture. Suitable metals for use with N-type silicon are gold, silver, platinum or palladium. In a further method of producing a metal contact of the required shape an aperture is formed in the silicon monoxide layer 5 by depositing a layer of nickel or aluminium over that part of the silicon dioxide layer 4 where the aperture is required then applying the layer of silicon monoxide of less thickness than the metal layer so that it is interrupted by the edge of the metal layer, and etching to remove the metal layer with its covering oxide layer to leave a hole through which the silicon dioxide layer can be etched to give a flared aperture as before. |
