A device is formed in a semiconductor body having a major surface, with an insulating coating over the surface having an aperture exposing a portion thereof. A polycrystalline semiconductor layer is disposed in the aperture and over the coating, and a refractory metal layer overlies a portion of the semiconductor layer. A metal layer having low temperature properties overlies another portion of the semiconductor layer and is spaced from the refractory layer by a third portion of the semiconductor layer which provides metallurgical isolation and selective resistance between the two metal layers. Termination means contacts the low temperature layer.
A polysilicon interconnect is formed on a microelectronic circuit substrate for conducting signals from a driver to a non-polycrystalline silicon contact which has higher impedance than the interconnect. A plurality of electronic "speed bumps" are spaced along the interconnect for disturbing or disrupting signals propagating along the interconnect toward the contact and thereby reducing undesirable back reflection and ringing. The speed bumps can include capacitance altering elements in the form of dielectric strips, or resistance altering elements in the form of low resistance doped areas or high resistance amorphous areas. The speed bumps can include first and second elements having different values of capacitance or resistance which are spaced along the interconnect in alternating relation.
In a semiconductor integrated circuit, an insulating film is formed on a major surface of the substrate. An elongated wiring layer including a polycrystalline silicon layer is formed on the insulating layer. At least one metallic area is formed over the wiring layer except at the ends of the wiring layer.
Regions of high resistivity, with respect to the surrounding material, are designed into a semiconductor device at points where hot-spots have been observed. A device made in this manner has very good second breakdown characteristics. One application is in large area junction transistors having an interdigitated base-emitter configuration.
A voltage-variable capacitor having a relatively high figure of merit, Q, and thus useful at relatively high frequencies, includes a thin layer of epitaxial semiconductive material on a highly doped semiconductor substrate. An apertured dielectric layer is disposed on the epitaxial layer and a layer of material capable of making rectifying contact to the semiconductive material is disposed on the dielectric layer, with a portion thereof extending into an aperture in the dielectric layer into rectifying contact with the epitaxial layer. This construction eliminates the need for a diffused, minority-carrier-collecting junction, thereby allowing the epitaxial layer to be thin and the series resistance of the device to be low.
