Abstract: Briefly stated, the present invention provides a vertical current flow semiconductor device (17). The vertical current flow semiconductor device (17) includes a semiconductor substrate (12) having an intermediate conductor layer (16) on a surface of the substrate (12). An active layer (11) that is used for forming active elements (20, 21, 22, 23) of the vertical current flow semiconductor device (17) is on the intermediate conductor layer (16). The intermediate conductor layer (16) forms an ohmic contact with the active layer (11).

Abstract: A p.sup.- semiconductor substrate has a surface which is high in a memory cell region and low in a peripheral circuit region. An n.sup.+ buried semiconductor layer of uniform thickness is formed on the substrate. An n.sup.- epitaxial layer formed on the buried semiconductor layer is thin in the memory cell region and thick in the peripheral circuit region, so that the surface of the epitaxial layer can be flat. A concave or convex step is formed on the surface of the epitaxial layer in a boundary portion between the memory cell region and the peripheral circuit region in order to use it as an alignment mark in a later processing step.

Abstract: A low capacitance radiation detector comprises a monocrystalline silicon substrate heavily doped to N type conductivity with a more lightly doped N type conductivity epitaxial layer formed on the substrate. A plurality of heavily doped N type upper surface layer segments are formed in the epitaxial layer. A patterned region of the epitaxial layer, heavily doped to P type conductivity and in the shape of parallel stripes joined at each end by a respective stripe perpendicular to the parallel stripes, is formed in the epitaxial layer and situated between adjacent ones of the upper surface layer segments, with each stripe extending into the epitaxial layer deeper than, and separated from, the upper surface layer segments so as to form a minority charge carrier-collecting PN junction with the epitaxial layer.