A memory in which each cell comprises an MOS transistor merged with a storage capacitor and in which the cells are arranged to permit adjacent pairs of transistors in a common column to share a common source and the transistors in a common row to share a common gate electrode conductor. The memory uses a first polycrystalline silicon layer which is patterned to provide interconnected storage electrodes and a second polycrystalline silicon layer which is patterned to provide a plurality of stripes to serve as the bit sense lines and a plurality of gate electrodes.
An MOS integrated semiconductor memory is disclosed with memory locations arranged in lines and columns. The memory locations in each case contain two one-transistor memory cells. For each memory location, two MOS transistors of the two one-transistor memory cells are controlled in common by means of a word line which runs in a line direction. The two MOS transistors are each coupled on a respective bit line which runs on one side of the memory locations in a column direction. Electrodes of the MOS memory capacitors and the gates of the MOS transistors of the one-transistor memory cells are formed by a first polysilicon layer and a second polysilicon layer, respectively. For reduction of area and also of bit line capacitance as well as at the same time raising the memory capacitance, the invention provides that the bit lines are provided as a third polysilicon layer forming polysilicon paths, and that the polysilicon paths which form the bit lines are coupled on only via limited doped connection zones in a semiconductor substrate which contains the memory cells of the MOS transistors.
A method for forming semiconductor memory devices each including either an MNOS-type or MOS-type transistor and an MNOS-type capacitor. Upon a silicon substrate there is formed a thick layer of oxide which defines the individual cells and provides separation therebetween. Exposed portions of the substrate are thermally oxidized to form a layer of thermal oxide upon which is subsequently deposited a layer of silicon nitride and a layer of polycrystalline silicon. The polycrystalline silicon is then masked and portions there are removed through apertures and the mask. The substrate is then irradiated at a non-perpendicular angle through the apertures in the mask and predetermined remaining portions of the layer of thermal oxide are removed. Exposed portions of the substrate at this point are diffused with an impurity of the opposite conductivity type to the substrate. A second polycrystalline silicon layer is then formed to provide bit lines for each memory cell and simultaneously an opposing electrode of the corresponding capacitors. A second thick oxide layer is then formed with a metal interconnection layer deposited thereon for forming the connection lines to each memory cell.
A method for making highly dense, dielectrically isolated, U-shaped MOSFET. In a preferred method a monocrystalline silicon P substrate with a N+ layer thereon, a P layer on the N+ layer and a N+ layer on the P layer is provided. A pattern of U-shaped openings is formed in the body through to the P substrate by the reactively ion etching technique. This pattern of openings is filled with an insulator material, such as silicon dioxide. A conductive layer of N+ doped polycrystalline silicon is deposited on the bare surface of this silicon body. Openings are formed in the polycrystalline silicon over the silicon dioxide filled openings. A silicon dioxide layer is then grown by, for example, thermal oxidation over the polycrystalline silicon layer. Reactively ion etching is used to produce substantially U-shaped openings through the layers over the P substrate and into the P substrate to substantially bisect the regions of monocrystalline silicon. This etching step forms two storage cells in the monocrystalline silicon areas and a bit line for each column of cells in the polycrystalline silicon layer. A silicon dioxide gate insulator is grown on the monocrystalline silicon surfaces of the U-shaped openings by thermal oxidation in a suitable ambient. Conductively doped polycrystalline silicon is deposited in the U-shaped openings over the silicon dioxide gate insulator layer until the openings are filled and cover the surface of the body. The conductively doped polycrystalline silicon on the surface of the body is etched in a suitable pattern to produce the word lines of the random access memory device.
The gate array (10) has a first doped region (14) in a semiconductor substrate (12) and a plurality of contacts (20-20"', 21-21") arranged in rows and columns to the first doped region (14) organized with contacts of each row offset in a column (25) that is spaced with respect to a columns (28) of adjacent rows at which a contact exists. A plurality of gate conductors (35-42) are arranged to circumnavigate successive contacts (20,21) of adjacent rows on opposite sides in a serpentine patterns, preferably that follow partially circular paths. The contacts (20,21) are substantially circular in cross section, and may be provided with cap (32) on each that may also have a substantially circular cross section. The contacts (20-21) are spaced with a predetermined pitch and the gate conductors (35-42) have a width that defines transistor channels between adjacent contacts. The width of the conductors (35-42) allows the conductors to pass in proximity to the contacts (20-21) with a predetermined spacing. The gate array (10) may have in the substrate a second doped region (15) of an opposite conductivity type from a conductivity type of the first doped region (14). A gate array similar to that constructed above the first doped region is constructed above the second doped region to enable diverse logic circuits to be constructed by selective interconnections among selected contact and gate conductors (50,51).
Method for manufacturing dynamic RAM one-transistor storage cells in a semiconductor chip with each cell having one integrated field effect transistor and one integrated capacitor. A semiconductor substrate surface is covered in part by a thin oxide layer and in part by a thick oxide structure. The thin oxide layer is subjected to a first ion implantation. A doped polycrystalline semiconductor material is deposited over the entire surface. The polycrystalline layer is structured by means of a photoresist mask and the underlying layers at the open places etched away to expose substrate surface. The mask is removed. A second thin oxide layer is created by oxidation over the entire surface. A second ion implantation implants ions in the second oxide layer. A second doped layer of polycrystalline material is deposited over the second layer. The second polycrystalline layer is structured by a suitable phototechnique to produce a polycrystalline structure semiconductor layer.
