Abstract: A method was achieved for making improved self-aligned contacts (SAC) to a patterned polysilicon layer, such as gate electrodes for FETs. Lightly doped source/drain areas are implanted. A second insulating layer is deposited and etched back to form first sidewall spacers. A silicon nitride etch-stop layer and a first interpolysilicon oxide (IPO1) layer are deposited. First SAC openings are etched in the IPO1 layer to the etch-stop layer, and concurrently openings are etched for the gate electrodes, eliminating a masking step. The etch-stop layer is etched in the SAC openings to form second sidewall spacers that protect the first sidewall spacers during BOE cleaning of the contacts. A patterned polycide layer is used to make SACs and electrical interconnections. A second IPO layer is deposited to provide insulation, and an interlevel dielectric layer is deposited.

Abstract: A new method of forming an improved buried contact junction is described. A gate oxide layer is provided over the surface of a semiconductor substrate. A first polysilicon layer is deposited over the gate oxide layer. A photoresist mask is formed over the first polysilicon layer having an opening over the planned buried contact. The first polysilicon layer not covered by the photoresist mask is etched away. A portion of the photoresist mask at the edges of the opening is cut away to expose a portion of the first polysilicon layer at the edges of the opening. The gate oxide layer not covered by the mask is etched away using a reduced etching selectivity of oxide to silicon so that an upper portion of the first polysilicon layer exposed at the edges of the opening is etched away leaving a thinner first polysilicon layer at the edges of the opening. Ions are implanted through the opening and through the thinner first polysilicon layer into the semiconductor substrate to form the buried contact.

Abstract: An SRAM device has STI regions separated by mesas and doped regions including source/drain regions, active areas, wordline conductors and contacts in a semiconductor substrate is made with a source region has 90.degree. transitions in critical locations. Form a dielectric layer above the active areas. Form the wordline conductors above the active areas transverse to the active areas. The source and drain regions of a pass gate transistor are on the opposite sides of a wordline conductor. Form the sidewalls along the <100> crystal plane. Form the contacts extending down through to the dielectric layer to the mesas. Substrate stress is reduced because the large active area region formed in the substrate assures that the contacts are formed on the <100> surfaces of the mesas are in contact with the mesas formed on the substrate and that the <110> surfaces of the silicon of the mesas are shielded from the contacts.

Abstract: The present invention provides a novel method for fabricating a buried contact extending under the first conductive layer 16 and subjacent first insulating layer 14. A first insulating layer 14 and a first conductive layer are formed over a silicon substrate 10 having isolation structures 12. A photoresist mask 18A having a buried contact opening 20 is formed over the first conductive layer. The first conductive layer 16 and the first insulating layer 14 are etched through the photoresist mask 18A. A width 21 of the photoresist mask 18A adjacent to the buried contact opening 20 is removed using a descum process, thereby forming an expanded opening 20A and an exposed ring 16A of the first conductive layer 16 with subjacent first insulating layer 14.

Abstract: A process for forming a borderless contact opening to an active device region, overlaid with a metal silicide layer, has been developed. The borderless contact opening is formed in a composite insulator layer, comprised with an overlying, thick ILD layer, and a thin, underlying silicon oxynitride layer. The thin silicon oxynitride layer, used as a etch stop layer, during the anisotropic RIE procedure used to form the borderless contact opening, is deposited at a temperature below 350.degree. C., to prevent agglomeration of the metal silicide layer.

Abstract: The present invention provides a method of inter-poly oxide (IPO) layer underlying a polysilicon resistor in a memory product. The IPO layer 15 is formed by a modified low pressure SACVD-O.sub.3 -TEOS process that gives the IPO layer a smoother surface and good planarization. This IPO layer gives the overlying polysilicon resistors a more uniform resistance. The method begins by providing a semiconductor structure 10. Next, in an important step, an inter-poly oxide (IPO) layer 11 is formed using low pressure ozone assisted sub-atmospheric chemical vapor deposition (SACVD O.sub.3 -TEOS) process at a pressure between about 20 and 150 torr. A polysilicon resistor 15 is then formed on said inter-poly oxide (IPO) layer. The memory device is completed by forming passivation and conductive layers thereover.

Abstract: A method for providing a chemical mechanical polishing planarization process for preventing multi-polysilicon and multi-metal level electrical shorts, which includes briefly the sequential processing steps of i) providing an insulating layer to a first thickness over a device wafer with non-planar surface topography; ii) chemical-mechanical polishing the first insulating layer; and iii) deposition of another polysilicon layer of second thickness to prevent the barely exposed or exposed underlying polysilicon from shorting to the next polysilicon or metal level of interconnects.

Abstract: A new method of forming an improved buried contact junction is described. A gate silicon oxide layer is provided over the surface of a semiconductor substrate. A polysilicon layer is deposited overlying the gate oxide layer. A hard mask layer is deposited overlying the polysilicon layer. The hard mask and polysilicon layers are etched away where they are not covered by a mask to form a polysilicon gate electrode and interconnection lines wherein gaps are left between the gate electrode and interconnection lines. A layer of dielectric material is deposited over the semiconductor substrate to fill the gaps. The hard mask layer is removed. The polysilicon layer is etched away where it is not covered by a buried contact mask to form an opening to the semiconductor substrate. Ions are implanted to form the buried contact.

Abstract: An improved and new structure and method for forming a guard ring in an integrated circuit having at least one level of polysilicon wiring has been developed. The guard ring is formed without necessitating additional manufacturing process steps and the guard ring is bonded to the semiconductor substrate, thereby providing a superior barrier to diffusion of moisture and contaminants from a window in the insulating layers to the semiconductor device regions.

Abstract: A three dimensional polysilicon resistor and a method by which the three dimensional polysilicon resistor is manufactured. A semiconductor substrate has formed upon its surface an insulating layer. The insulating layer has a minimum of one aperture formed at least partially through the insulating layer. A polysilicon layer is formed upon the insulating layer and formed conformally into the aperture(s) within the insulating layer. The polysilicon layer is then patterned to form a resistor which includes the portion of the polysilicon layer which resides within the aperture(s).

Abstract: A process for manufacturing a thin film transistor for use in a CMOS SRAM circuit is described. A key feature is the formation of two different photoresist masks from the same optical mask. The first photoresist mask is generated using a normal amount of actinic radiation during exposure and is used to protect the gate region during source and drain formation through ion implantation. The second photoresist mask is aligned relative to the gate in exactly the same orientation as the first mask but is given a reduced exposure of actinic radiation. This results, after development, in a slightly larger mask which is used during etching to form the oxide cap that will protect the channel area during the subsequent silicidation step. Making the cap slightly wider than the channel ensures that small lengths of the source and the drain regions that abut the channel are not converted to silicide. Thus, the finished device continues to act as a thin film transistor, but has greatly reduced source and drain resistances.

Abstract: A method for fabricating thin film transistors (TFTS) for SRAM devices is described having metal shields over the channel regions for improved electrical characteristics. The method involves forming N.sup.+ doped polysilicon TFT gate electrodes having a gate oxide thereon. An N.sup.- doped amorphous silicon is deposited and recrystallized. The recrystallized silicon is P.sup.+ doped to form the TFT source/drain areas and patterned to form the N.sup.- doped channel regions with P.sup.+ source/drain areas. After depositing an insulating layer, a metal layer is deposited and patterned to completely cover and shield the TFT channel regions from ion damage during the plasma hydrogenation which is subsequently performed. The patterned metal layer also serves as the bit lines for the SRAM device. The plasma hydrogenation reduces the surface states at the gate oxide channel interface, while the shielding effect of the metal layer from ion damaging radiation reduces the off current (I.sub.off), increases the I.sub.

Abstract: A fabrication process for integrating stacked capacitor, DRAM devices, and thin film transistor, SRAM devices, has been developed. The fabrication process features combining key operations used to create transfer gate transistor structures, and access transistor structures for the DRAM and SRAM devices. In addition, process steps, used to create a capacitor structure, for the DRAM device, and a thin film transistor structure, for the SRAM device, are also shared. Another key feature of this invention is a buried contact structure, used for the SRAM device.

Abstract: A method is achieved for making TFT-load static random access memory (SRAM) cells where the thin film transistor (TFT) gate electrodes are made from an electrical conductor. At the same time, portions of the conductor between P and N doped polysilicon interconnections eliminate the P/N junction. Ohmic contacts are formed while avoiding additional processing steps. N-channel FET gate electrodes are formed from an N.sup.+ doped first polysilicon layer having a first insulating layer thereon. Second polySi interconnections are formed with a second insulating layer thereon. First contact openings are etched in the first and second insulating layers to the N.sup.+ doped FET gate electrodes, and a patterned conductor (TiN, TiSi.sub.2) forms the P-channel TFT gate electrodes and concurrently forms portions over and in the first contact openings. A TFT gate oxide is formed and second contact openings are etched over the first contact openings to the conductor. An N.sup.

Abstract: A fabrication process for integrating stacked capacitor, DRAM devices, and thin film transistor, SRAM devices, has been developed. The fabrication process features combining key operations used to create transfer gate transistor structures, and access transistor structures for the DRAM and SRAM devices. In addition, process steps, used to create a capacitor structure, for the DRAM device, and a thin film transistor structure, for the SRAM device, are also shared. Another key feature of this invention is a buried contact structure, used for the SRAM device.

Abstract: A process is provided in which silicon thin film transistors fabricated with polycrystalline silicon, silicon oxide, and silicon conductive layers are exposed to microwave plasmas containing water vapor and to subsequent annealing steps to bring about an improvement in the ratio of device drain current in the conductive state to that in the non-conductive state, and a lower device subthreshold voltage swing.

Abstract: A method for fabricating thin film transistors (TFTs) for SRAM devices is described having metal shields over the channel regions for improved electrical characteristics. The method involves forming N.sup.+ doped polysilicon TFT gate electrodes having a gate oxide thereon. An N.sup.- doped amorphous silicon is deposited and recrystallized. The recrystallized silicon is P.sup.+ doped to form the TFT source/drain areas and patterned to form the N.sup.- doped channel regions with P.sup.+ source/drain areas. After depositing an insulating layer, a metal layer is deposited and patterned to completely cover and shield the TFT channel regions from ion damage during the plasma hydrogenation which is subsequently performed. The patterned metal layer also serves as the bit lines for the SRAM device. The plasma hydrogenation reduces the surface states at the gate oxide channel interface, while the shielding effect of the metal layer from ion damaging radiation reduces the off current (I.sub.off), increases the I.sub.

Abstract: A method for fabricating buried metal plug structures for multi-polysilicon layer interconnects and for concurrently making metal plugs on semiconductor integrated circuits, such as DRAM and SRAM, was achieved. The method involved forming contact opening in an insulating layer over opening in a patterned polysilicon layer. The opening in the polysilicon layer aligned over source/drain contact areas on the substrate and providing a means for forming self-aligned contact openings. Buried metal plugs in the contact openings form interconnects between the polysilicon layer and the source/drains. And, by merging the process steps, concurrently forming metal plug interconnects for contacts to semiconductor devices and first level metal. The process is applicable to the formation of bit line contacts on DRAM and SRAM circuits and simultaneously form the peripheral contact on the chip.

Abstract: A process for fabricating SRAM cells, including MOSFET devices, as well as thin film transistor structures, has been developed. The process features self-alignment of the MOSFET polysilicon gate structure to the polysilicon gate structure of the thin film transistor. Self-alignment is accomplished via a photolithographic and dry etching patterning procedure, applied to a combination of polysilicon, and insulator layers, resulting in the desired polysilicon gate structures for both the MOSFET and thin film transistor devices.

Abstract: Reduced area metal contacts to a thin polysilicon layer contact structure having low ohmic resistance was achieved. The structure involves forming contact openings in an insulating layer over a buffer layer composed of a thick polysilicon layer. A portion of the sidewall in the opening includes a patterned thin polysilicon layer that forms part of a semiconductor device and also forms the electrical connection to the metal contact. The structure provides metal contacts having very low resistance and reduced area for increased device packing densities. The metal contact structure also eliminates the problem of forming P.sup.+ /N.sup.+ non-ohmic junctions usually associated with making P.sup.+ /N.sup.+ stacked contact. The structure further allows process steps to be used that provide larger latitude in etching the contact opening and thereby provides a structure that is very manufacturable.