Semi-conductor circuit and method of making same

摘要

925,520. Monogrammic signs. BURROUGHS CORPORATION. Feb. 15, 1961 [Feb. 25, 1960], No. 5658/61. Class 118. [Also in Group XXXVI] A semi-conductor diode matrix for use, e.g., with a visual display device, comprises a number of strips of semi-conductor material, each strip having one or more integral protrusions forming separate unidirectional current conducting devices. As shown, Fig. 1, a wafer 11 of N-type silicon has a layer of acceptor impurity such as boron vapourdeposited on one surface and diffused into the wafer at c. 1300‹ C. to form a P-N junction below the said surface. Alternatively, the wafer may be P-type and have a layer of N- type impurity such as phosphorus diffused in; also germanium may be used. The wafer may then be coated with silver or other conductive material. It is next machined ultrasonically to remove portions of P-type material and the adjacent N-type material to a depth below the P-N junction, leaving upstanding mesas 13 each comprising a P-N junction. The matrix thus formed is placed on a base 25 of porcelain &c., Figs. 4 and 5, so that each mesa 13 contacts a predetermined one of a plurality of conductive paths 21 printed in silver, palladium, &c. and fired on to the base. -The assembly is fired or cured to bond the mesas 13 to the conductive paths 21 and the end portions 16 of the wafer to connectors 23. The wafer is ultrasonically sliced between rows of mesas in a direction perpendicular to conductive paths 21 to form strips of semi-conductor material such as 15a, each being connected via a connector 23 to a terminal 31 representing a digit. A signal applied to a terminal 31 energizes, through the mesas of its associated strip and the relevant conductive paths 21, elements of a display device 19 to provide a visual display of the appropriate digit. The elements may be cathodes of a neon tube device having a common anode. Preferably, the strips and adjacent printed circuits are potted in glass, epoxy resin &c. Fig. 6 (not shown), depicts an alternative printed circuit arrangement.