| 摘要 |
<p>1,100,708. Semi - conductor devices. WESTERN ELECTRIC CO. Inc. 17 June, 1965 [23 June, 1964], No. 25617/65. Heading HlK. In a device having a metal-to-semi -conductor rectifying junction, the metal layer consists of two different metals in contact with each other, both contacting a surface of the semi-conductor. The metal having the lower barrier potential defines the effective junction and the other metal provides a contact area for an electrode lead. In Fig. 1, an N-type silicon wafer 11 has been provided-eg. by vapour phase deposition through a surface oxide mask-with an annular deposit 12 of platinum which may, but need not, be alloyed to the silicon. The platinum serves as a mask for deposition of a circular layer 13 of tungsten inside the platinum annulus. An electrode lead 14 is attached, e.g. by thermocompression bonding, to the platinum and an ohmic contact 15 is made to the opposite face of the wafer, thus completing a diode in which the metal electrode connection is to the platinum, the junction effectively being that between the tungsten and the silicon. If the silicon is P-type the roles of platinum and tungsten are reversed. The invention may also be applied to germanium and gallium arsenide semi-conductors. The platinum may be replaced by gold or vanadium and the tungsten by molybdenum, silver or copper. The lower barrier metal may also be of calcium, magnesium, lithium or sodium provided that the higher barrier metal, to which the electrode lead will be attached, completely covers and protects it from the atmosphere. In Fig. 2 (not shown), a diode differing from that described above only in that the metal layers are contiguous rectangles has been converted into a metal base transistor by deposition on the metal layer constituting the effective barrier of further semi-conductor material, which need not be the same semi-conductor as the underlying wafer.</p> |
