| 摘要 |
964,178. Semi-conductor devices. PHILIPS ELECTRICAL INDUSTRIES Ltd. June 2, 1961 [June 7, 1960], No. 19981/61. Drawings to Specification. Heading H1K. In a method of manufacturing a semiconductive device, a body of gallium arsenide having at least one asymmetrically conductive junction and provided with at least one electrode is subjected to an electrolytic etching treatment in an alkaline bath, the electrode or at least one of the electrodes being used to apply a voltage to the body positive with respect to the etching bath. The etching liquid may comprise an aqueous solution of sodium hydroxide, potassium hydroxide, a mixture of the two, or 30% aqueous ammonia. A highspeed switching alloy diode may be produced by providing a P-type gallium arsenide wafer with an ohmic electrode produced by alloying an indium pellet to the wafer in a hydrogen atmosphere at 550% using ammonium bifluoride as a flux, and with a rectifying contact by similarly alloying a gold/tin/arsenic alloy bead to the opposite surface of the wafer at 500‹ C. Nickel leads are joined to the electrodes and the device immersed in a 40% potassium hydroxide solution, either one or both of the leads being connected to the positive side of a power supply and the circuit completed through a platinum cathode immersed in the solution. Etching takes place around the PN junction and a shallow groove is etched under the rectifying electrode thus limiting the area of the PN junction, the rate and degree of etching being dependent only on the electrolytic current. A tunnel diode may be produced in a similar way from a heavily zinc-doped body, but in this case uniform etching occurs over most of the body because of its low resistivity although preferential etching still occurs around the PN junction.
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