Abstract:
A nondestructive read-integrated circuit memory cell consisting of a pair of cross coupled transistors. The junctions between the collectors of the transistors and the intrinsic epitaxial layer is utilized to provide isolation between the transistors. The transistors are formed by a triple-diffusion process wherein the collector region contacts a buried layer of opposite semiconductivity relative to the semiconductivity of the substrate structure. An epitaxial growth being of the same semiconductivity as the buried layer region is utilized as both a resistive material between the input and the buried layer and to form a diode gradient between the epitaxial region and the collector region of the transistors. The buried region forms a diode junction with the collector regions of the transistor to allow a bilevel operation of the memory cell.
Abstract:
A semiconductor device containing in a single semiconductor body a self-aligned Field Effect Transistor and a Charge-Coupled Array having an improved capacity for storing charges. The device is formed by depositing both polysilicon and silicon nitride layers over a silicon dioxide layer on the surface of a silicon body and selectively etching these layers so that suitable dopants may be diffused or ion-implanted into selected areas of the underlying silicon body to form, in the same semiconductor body, an improved charge-coupled array having an improved self-aligned Field Effect Transistor associated therewith. This process not only results in a device in which the chance of an inversion layer under the oxide on the surface of the device is substantially reduced, but also provides a self-aligned Field Effect Transistor having a thinner gate oxide and a charge-coupled array that has an increased capacity for storing charges. The improved array so formed also has, during operation, zero spaced depletion regions so that unwanted electrical discontinuities between or within the depletion regions of the charge-coupled array are avoided. Because zero spacing is achieved by using these thin conducting layers, the metal phase lines can be made narrow thus leaving openings in the charge transfer channel making the device particularly suitable for imaging applications.
Abstract:
A process wherein epitaxial silicon is grown on a substrate of single-crystal silicon with islands of silicon dioxide thereon, whereby single crystal epitaxial material is grown over the single-crystal substrate areas, but polycrystalline silicon is grown over the silicon dioxide islands. Since impurity diffusion occurs more rapidly through polycrystalline material than through single-crystalline material diffusion schemes can be obtained using the rapid diffusion pathway provided by the polycrystalline material to provide subsurface configurations which are completely enclosed by single-crystal material, for instance, a buried subcollector can be formed by growing polycrystalline silicon material horizontally, extending a narrow polycrystalline channel upward to the device surface, and subsequently diffusing impurities down through the narrow vertical polycrystalline channel into the lateral polycrystalline subcollector. Further, an electrical underpass can be formed which has a very low resistance by again using the rapid diffusion characteristics of polycrystalline silicon to grow polycrystalline silicon of the desired shape which can be rapidly diffused to provide, in comparison to background, a high conductivity path. By control of the substrate crystalline orientation, polycrystalline material can be grown which terminates because of sidewall convergence. This is desirable where it is required to terminate polycrystalline growth and begin single-crystal growth without any alteration in process conditions. The devices described are also claimed.