Improvements in or relating to semiconductor junction devices

1,074,672. Semi-conductor devices. PLESSEY-U.K. Ltd. April 2, 1964 [April 22, 1963], No. 15806/63. Heading H1K. A PN junction 13a is formed between regions of opposite conductivity types in a semiconductor body 10 and reaches the surface of the body in an area covered by a masking layer 11, and an electrical connection to one region 13 is provided by an electrolytically deposited metallic layer 16 extending over that part of the surface of the region 13 which is not covered by the masking layer 11 and also over the layer 11 at least as far as the junction 13a. As described, a slice 10 of N-type silicon is provided with an oxidized layer 11 which acts as a mask for the diffusion of boron through an aperture 12 to form a P-type region 13. A ring of chromium is evaporated on to the oxide layer 11 surrounding the aperture 12, and lead, cadmium or tin is electroplated on to the exposed surface of the region 13 and allowed to extend over the chromium-covered part of the oxide layer 11. The electro-deposited metal is then melted so that surface tension forces pull the molten metal into a globule (the chromium not being wetted by the molten metal) which, upon cooling, solidifies into a raised contact portion 16. Alternatively, the electrodeposited metal may be fused to a copper ball which will then form the raised contact portion.