SEMICONDUCTOR DEVICE

1,003,131. Semi-conductor devices. INTERNATIONAL BUSINESS MACHINES CORPORATION. April 23, 1964 [May 24, 1963], No. 16777/64. Heading H1K. In the manufacture of a semi-conductor device from a body of semi-conductor material comprising first and second layers of opposite conductivity type, the first layer having a higher resistivity than the second layer, an impurity is diffused through one or more selected areas of that surface of the first layer which faces away from the second layer, so that parts of the first layer are converted to the same conductivity type as the second layer and these converted parts join with at least some of the material from the original second layer to form a unitary mass of semi-conductor material all of the same conductivity type, the converted parts adjoining unconverted parts of the first layer. As shown, boron is diffused through photo-engraved apertures 24 in a silicon dioxide mask 23 into a vapour-deposited epitaxial N-type first layer 21 to form P-type regions extending through the N-type layer 21 to join the P-type region formed by diffusion from the original P+ second layer 20. The silicon dioxide layer is restored and is covered with a coating of glass, and ohmic connections are made through holes etched in these layers. Embodiments described include a double diode, Figs. 2D and 2E (not shown), and a transistor, Figs. 4A to 4D (not shown). The object of the invention is to produce a semiconductor device free from surface inversion. Specification 994,814 is referred to.