Abstract: A technique for producing self-aligned contact openings is especially useful when the openings are to be made between conductive structures having relatively small separation. Formation of an oxide layer under particular process conditions results in a thicker layer of oxide on top of the conductive structures, and a thinner oxide layer along the sidewalls and in the bottom of the spacing between them. Deposition of such a differential thickness oxide layer can be followed by an unmasked-anisotropic etch in order to clear the oxide from the space between the conductive structures, without removing all of the oxide layer over the conductive structure. Such a technique can be utilized in integrated circuits such as DRAMs, with the word lines allowing for the formation of semi-self-aligned bit lines. The combination of word lines and bit lines can provide for a fully self-aligned contact opening for DRAM cell capacitors.

Abstract: A method for forming a SRAM structure with polycrystalline P-channel load devices of an integrated circuit, and an integrated circuit formed according to the same, is disclosed. A field oxide region is formed over a portion of the substrate. A first gate electrode of a first N-channel field effect device is formed over the substrate having a source/drain region in the substrate. A second gate electrode of a second N-channel field effect device is also formed over the substrate and a portion of the field oxide. A first insulating layer is formed over the integrated circuit containing an opening exposing a portion of the source/drain region and the second gate electrode of the first and second N-channel devices respectively. An interconnect layer having a doped polysilicon layer and a barrier layer is formed over the integrated circuit, patterned and etched to define a shared contact region covering the exposed source/drain region and the second gate electrode of the N-channel devices.

Abstract: A capacitor suitable for use with a DRAM memory cell is composed of multiple layers of polycrystalline silicon. The storage node is formed from a polycrystalline silicon layer sandwiched between two polysilicon ground plate layers. Such a structure nearly doubles the capacitance for a given chip surface area used. First the bottom polycrystalline silicon plate layer is fabricated, followed by an isolation step and fabrication of the storage node polycrystalline silicon layer. Following another isolation step, the polycrystalline silicon top plate layer is then formed and connected to the bottom plate layer.

Abstract: A method for forming a SRAM structure with polycrystalline P-channel load devices of an integrated circuit, and an integrated circuit formed according to the same, is disclosed. A first gate electrode of a first N-channel field effect device is formed over the substrate having a source/drain region in the substrate. A second gate electrode of a second N-channel field effect device is also formed over the substrate and a portion of a field oxide. A metal containing layer is formed over the second gate electrode and the source/drain region of the first N-channel device to define a shared contact region. A first conductive layer is formed over the metal containing layer, patterned and etched to define a first and a second gate electrode of a first and a second P-channel field effect device respectively. A second conductive layer is formed over a portion of the first and second P-channel devices, to define a source/drain and channel region of the P-channel devices.

Abstract: A semiconductor device is described in which a conductive layer overlaps a dielectric layer forming a composite electrical device deposited over selected portions of a semiconductor substrate chemically isolating the conductive layer portion of the composite electrical device from the substrate, thereby preventing diffusion of dopant material through the dielectric layer into and out of the conductive layer while simultaneously allowing for tunneling of electrons through the dielectric layer to and from the conductive layer and the semiconductor substrate.

Abstract: The method for fabrication of openings in semiconductor devices to improve metal step coverage includes forming an active region over a substrate. A metal oxide layer is then formed over the source/drain region. An insulating layer is formed over the metal oxide layer. A photoresist layer is formed over the insulating layer, and patterned to form an opening, exposing a portion of the insulating. The insulating layer is then etched to expose a portion of the metal oxide layer. The photoresist layer is removed and the insulating layer is reflowed so as to form rounded corners at the opening of the insulating layer. The exposed portion of the metal oxide layer is removed to expose a portion of the active region.

Abstract: A capacitor suitable for use with a DRAM memory cell is composed of multiple layers of polycrystalline silicon. The storage node is formed from a polycrystalline silicon layer sandwiched between two polysilicon ground plate layers. Such a structure nearly doubles the capacitance for a given chip surface area used. First the bottom polycrystalline silicon plate layer is fabricated, followed by an isolation step and fabrication of the storage node polycrystalline silicon layer. Following another isolation step, the polycrystalline silicon top plate layer is then formed and connected to the bottom plate layer.

Abstract: A semiconductor device is described in which a conductive layer overlaps a dielectric layer forming a composite electrical device deposited over selected portions of a semiconductor substrate chemically isolating the conductive layer portion of the composite electrical device from the substrate, thereby preventing difffusion of dopant material through the dielectric layer into and out of the conductive layer while simultaneously allowing for tunneling of electrons through the dielectric layer to and from the conductive layer and the semiconductor substrate.

Abstract: A method for forming a thin oxide layer structure includes the step of first growing a dry oxide layer. A layer grown in steam and chlorine is formed next, followed by a final dry oxide layer. An anneal step in an inert gas further improves the quality of the oxide layer. The structure formed by such a process provides a layer of steam grown oxide sandwiched between two layers of oxide grown in a dry atmosphere.

Abstract: A capacitor is formed for use with a DRAM storage cell by lying down alternating layers of polycrystalline silicon for the storage node and the ground plate. A buried bit line allows the capacitor area to cover a significant fraction of the cell layout area. The alternating storage node and ground plates of the capacitor are laid down alternately, and connected together as they are formed. The number of interleaved layers which can be used to form the capacitor can easily be varied to suit process requirements.

Abstract: Field oxide regions are formed between active regions of a silicon substrate by forming over the substrate a sandwich of silicon dioxide, silicon nitride and silicon dioxide layers, opening the layers to expose a portion of the silicon substrate, removing a layer of the exposed substrate, forming side wall spacers on the edges of the opening, removing a layer of the silicon substrate exposed between the side wall spacers, and then reaching the exposed substrate for the thermal oxidation of the exposed substrate for forming the field oxide region. In those structures in which the field oxide is buried in the substrate as shown in FIG. 12, it may be feasible to use thicker field oxide regions and thereby to reduce the need for the heavily doped surface layer under the field oxide.

Abstract: A method for increasing the width of a transistor includes first forming a nitride cap (14) over the substrate (10) and then forming trenches (24) and (26) on either side of the cap (14) and having tapered sidewalls (28) and (30). A conformal layer of nitride (32) is formed over the substrate and then anisotropically etched to form sidewall layers (34) and (36). Field oxide is grown in the trenches with birds beaks (42) and (44) extending upward under the sidewall layers (34) and (36). A portion of the sidewalls (28) and (30) of the trenches remain such that the overall surface area between the edges of the birds beaks (42) and (44) is increased. A layer of strip oxide is then grown on the substrate to provide rounded edges (47) and (49). The strip oxide is then removed by a fifty percent over etch to cause the birds beaks (42) and (44) to recede, thus further increasing the surface area.

Abstract: A method for making a CMOS integrated circuit device saves on masking steps by using unmasked blanket implantations at various steps of the process, such as setting the threshold voltages of the transistors, forming a lightly doped drain for the N-channel transistor, and for forming the source/drain regions of the N-type transistor.

Abstract: An improved method of planarizing a level of metallization employs a trench in a smooth-surfaced dielectric and a sequence of etching steps to cut the trench locally down to the substrate, while forming the main metallization pattern at the same time.