| 摘要 |
1286834 Semi-conductor devices GENERAL ELECTRIC CO 22 Oct 1969 [25 Nov 1968] 51840/69 Heading H1K An ohmic contact to a region of a semiconductor, e.g. silicon exposed through a layer of insulation consists of a layer of or topped with aluminium adjacent the region and an upper layer of readily solderable material such as gold, silver, tin and/or lead separated therefrom by a layer of material preventing interaction with the aluminium and comprising a layer of electroless nickel separated from the aluminium by a layer of palladium which may be deposited from a palladium chloride solution. Underlying the layer of aluminium may be a layer of one or more of titanium, vanadium and chromium. A conductive overlayer, e.g. of silver, may be vapour deposited on the barrier layer to facilitate selective application of the solderable material (gold) by electroplating through a photoresist mask. Subsequently any of the silver not plated with gold is etched away. Tincoated copper leads may be fused to the gold layers in a heated press, and the assembly consolidated by heating at 300-400‹ C. for 30 minutes. If desired lateral extensions of the contacts may be used as interconnections of an integrated circuit or as beam leads. |
