SE340027B - - Google Patents

Abstract

1,113,489. Semi-conductor devices. SIEMENS A.G. 10 Feb., 1967 [11 Feb., 1966], No. 6452/67. Heading H1K. Two non-contiguous closely adjacent regions 2a/2b and 2c of a semi-conductor surface are covered with doping and/or electrode-forming material 2, 4 by a process involving covering at least the first region 2a/2b with the material 2, covering the material 2 on the region 2a/2b with an etch-resistant layer 3 which leaves the second region 2c free, etching the region 2c, and then depositing the material 4 on to the region 2c. The etch-resistant layer 3 is then removed. In the embodiment shown the material 2 is deposited over the entire surface. The etchresistant layer 3 may be of a photo-varnish or of silicon dioxide, and during the etching process to remove the material 2 from the circular region 2c the layer 3 is slightly undercut, as shown. Deposition of the material 4 is then performed by vapour deposition or by a beam of material, such as by cathode sputtering or with an ion beam. The shade effect of the undercut thus separates material 4 from material 2. The etching of the region 2c may be continued so as to form a trough in the semi-conductor surface in which the doping or electrode material 4 is deposited. Additional masking, e.g. of etchresistant material, may be applied after removal of the excess material 2 to protect other parts of the surface against being covered by the material 4. The second region 2c may, in this case, be defined partly by the first etchresistant layer 3 and partly by the additional mask. The invention may be applied to transistors of planar or mesa form.