Abstract: This invention provides a stacked gate flash memory cell structure and a method for forming the stacked gate flash memory structure. The invention uses a large angle ion implant beam without wafer rotation to form the source and drain regions of the memory cell. A low doped region is formed between an edge of the first gate electrode and an edge of either the source or drain regions. The tunnel dielectric is formed directly above the low doped region. The width of the low doped region is controlled by the angle of the large angle ion implant beam and can be very accurately controlled. The tunnel dielectric is formed independently of the gate dielectric and the thickness of each can be optimized. The tunnel dielectric area can be made very small which improves reliability and reduces the voltage necessary to program and erase the memory cell.

Abstract: An static storage cell has 6 FETs, all of the same type. The cells are arrayed in columns that each have a pair of bit lines and rows that each have a word line. Each side of the cell has a pull down FET and a pull up FET and the two sides are interconnected to form a latch. The two nodes where the drain of one pull down FET and the gate of the other pull down FET are connected to the associated bit line through the associated one of two word pass FETs. The gates of the two pull up FETs and the two word pass FETs are connected to the word line. When the word line receives a selection voltage, the pull up FETs are enabled to conduct at a higher current level and the word pass FETs are enabled to apply the bit voltage to the associated node for a write operation or to apply the node voltage to the bit line for a read operation. At other times, the word pass FETs isolate the cell from the bit lines and the pull up FETs conduct at a sufficient current to maintain the latching operation of the cell.

Abstract: Fabrication of a MOSFET comprises, forming a dielectric layer on a substrate and a sacrificial structure on portions of the dielectric layer, forming a first polysilicon layer over the sacrificial structure and other exposed surfaces of the device, patterning the first polysilicon layer and the dielectric layer by masking and etching to form a stepped electrode structure partially upon the sacrificial structure and partially upon the other exposed surfaces of the device, applying ion implantation into the substrate outside of the area covered by the stepped electrode structure, removing the sacrificial laver from the surface of the substrate and from beneath the stepped electrode structure leaving an overhanging surface of the stepped electrode structure, forming a second layer of dielectric material on the exposed surfaces of the stepped electrode structure and the substrate, and forming a second polysilicon layer over and under overhanging portions the second layer of dielectric material and the substrate.

Abstract: An SRAM semiconductor device comprises a first layer, a second layer and a third layer of polysilicon are separated by dielectric layers formed on a substrate, and a split gate structure with transistors formed in different polysilicon levels. Preferably, the split gate structure includes pull down transistors and pass gate transistors formed in different polysilicon levels; the second polysilicon layer extends into contact with the substrate; the second polysilicon layer contacts the third polysilicon layer in an interconnection region; and the third polysilicon layer comprises a polysilicon load resistor.

Abstract: A ROM device includes cells with buried bit lines in a semiconductor substrate. A thin insulating layer covers the substrate has closely spaced, parallel, word lines formed thereon arranged orthogonally relative to the bit lines. The word lines are covered with reflowed glass insulating layers about 2500.ANG. thick. The glass insulating layers comprise a sublayer of undoped glass and an overlayer of doped glass, the underlayer about 500.ANG.-1500.ANG. thick and the overlayer about 1000.ANG.-1500.ANG. thick. An etched, patterned metal layer is formed on the glass insulating layer. The overlayer has been substantially removed by etching where the metal layer has been etched. An ion implantation pattern has been implanted into the substrate adjacent to the conductive lines. The device has been passivated. The implanted impurity ions having been activated by annealing the device.

Abstract: A new surface counter-doped lightly doped source and drain integrated circuit field effect transistor device is described. A gate silicon oxide layer is formed on the silicon substrate. A layer of polysilicon is deposited over the gate silicon oxide layer and etched to form a gate electrode structure. A first ion implantation is performed at a tilt angle to form lightly doped drain regions in the semiconductor substrate wherein the lightly doped drain regions are partially overlapped by the gate electrode structure. A second ion implantation is performed at a larger tilt angle and lower energy than the first ion implantation wherein the second ion implantation counter-dopes the surface of the lightly doped drain regions to form a very lightly doped drain layer thus making the lightly doped drain regions buried regions.

Abstract: A method of forming a retarded double diffused drain structure, and the resultant retarded double diffused drain structure, for a field effect transistor are described. A silicon substrate with field isolation regions and a gate structure is provided. A layer of photoresist is formed on the field isolation region, the silicon substrate, and the gate structure. The photoresist is patterned to expose the silicon substrate and the gate structure, but covers an area of the silicon substrate that is offset from the field isolation regions. A first ion implant is performed in a vertical direction in exposed regions of the silicon substrate, with suitable dopant having a high doping concentration. The photoresist is removed. A second ion implant is performed in a vertical direction in the silicon substrate, with suitable dopant with higher doping concentration than the first ion implant, in regions between the field isolation regions and the gate structure. The substrate is heated to drive in both the dopants.

Abstract: A system for rapidly producing an integrated circuit on a substrate using a curable liquid capable of solidification to form a photo-resist pattern corresponding to an artwork representation of interconnections when subjected to ultra-violet light energy operates with a processor and computer aided design software. The system includes an x-y table, an electronically erasable mask, a drawing device and a projecting system. The substrate is disposed on the x-y table. The curable liquid lies in a solidification plane on the substrate. The electronically erasable mask is an ultra-violet wavelength isolating image buffer and is electrically coupled to the processor. The drawing device may be a back lighted liquid crystal display or a high resolution cathode ray tube or an infrared diode laser raster scanner and electronically draws an image of the artwork representation for the interconnections onto the electronically erasable mask.

Abstract: A method of forming an ESD protection device with reduced breakdown voltage, simultaneously with an integrated circuit which includes FET devices, and the resultant device structure, are described. A silicon substrate is provided on which there are field oxide regions, gates, and active regions. A first ion implant of a conductivity-imparting dopant is performed in a vertical direction into the active regions of the ESD protection device and the FET devices. A first insulating layer is formed over the ESD protection device and the FET devices, and over the field oxide regions. The first insulating layer is patterned to create spacers adjacent to the gates of both the ESD protection device and the FET devices. A second ion implant of a conductivity-imparting dopant with higher concentration than dopant from the first ion implant is performed into active regions of both the ESD protection device and the FET devices.

Abstract: An improved process for fabricating a planar field oxide structure on a silicon substrate was achieved. The process involves forming the field oxide by using the LOCal Oxidation of Silicon (LOCOS) process in which the device area is protected from oxidation by a silicon nitride layer. A sacrificial leveling layer, such as spin-on-glass (SOG) or a anti-reflective coating (ARC) layer is used to fill in the gap between the silicon nitride and the field oxide structure and make more planar the substrate surface. The leveling layer is then etched back non-selectively by plasma etching to planarize the portion of the field oxide extending above the substrate surface. The method does not require a recess to be etched in the silicon substrate and therefore, has certain reliability and cost advantages.

Abstract: A method of fabricating an EPROM cell by forming a trench in a semiconductor substrate, forming a first insulating layer over the surface of the substrate, and the sidewalls and bottom of the trench, forming individual polycrystalline silicon layers on the sidewalls of the trench, implanting a dopant into the substrate in the bottom of, and regions adjacent, the trench, forming a second insulating layer over the polycrystalline silicon layers, forming a control gate over the polycrystalline silicon layers and an electrical contact to the bottom of the trench.

Abstract: A method for forming MOSFET devices, with an improved polycide gate has been accomplished. The polycide structure, made with metal silicide on polysilicon has a reduced rate of adhesion loss or peeling of the metal silicide from the underlying polysilicon, due to the unique surface of the polysilicon. The desired surface of the polysilicon, that will reduce the peeling phenomena, is a wavy or undulated surface. This is accomplished by either depositing the polysilicon at conditions that result in a hemi-spherical grained surface, or obtaining a similar wavy or undulated surface by treating smooth polysilicon in either phosphoric acid or by anodization in hydrofluoric acid. The adhesion of the subsequent metal silicide to the wavy surface of the polysilicon is improved to a point where peeling of the metal silicide from the underlying polysilicon is eliminated.

Abstract: A method of manufacturing a T-gate LDD pocket device is shown. Field oxide regions are formed in and on the surface of a semiconductor substrate. The T-gate device will be formed between the field oxide regions. A gate oxide layer is formed on the surface of the substrate between the field oxide. A layer of polysilicon is deposited over the gate oxide layer. Portions of the polysilicon layer are etched away leaving the polysilicon layer only between and over the inner edges of the field oxide. The remaining polysilicon is covered with a photoresist mask wherein the inner edges of the field oxide underlying the polysilicon are protected by the mask. The field oxide not covered by the mask are etched away to form the T-gate. A first set of ions of a first conductivity are implanted at a tilt angle to form lightly doped regions from regions where the field oxide have been removed and underlying the inner edges of the remaining field oxide.

Abstract: An EEPROM cell is made by forming a first dielectric layer on a substrate, forming a tunnel mask with an tunnel opening used for etching the dielectric layer to form a tunnel window, doping a region of the substrate through the tunnel window and stripping the tunnel mask. A spacer frame is made about the perithery of the window over the first doped region of the substrate. A second dielectric layer is formed over the first doped region within the spacer frame which is then removed. Tunnel oxide is deposited on the exposed surface of the first doped region, a floating gate layer is deposited, mask and etched. The mask is stripped Ions are implanted into buried N+ source/drain regions through exposed surfaces of the gate oxide near the floating gate. A blanket interconductor layer covers the device. A control gate layer is deposited, mask and etched. The control gate mask is then removed.

Abstract: This invention describes a device structure and a method of forming the device structure using trenches with sidewalls formed in the substrate of an integrated circuit. A highly doped polysilicon layer is formed on the walls of the trench or the trench is filled with highly doped polysilicon to form the source and drain of a field effect transistor in an integrated circuit. The invention provides reduced source and drain resistance. The capacitances between the gate and source and the gate and drain are reduced as well.

Abstract: An MOSFET device is fabricated with a plurality of conductors capacitively coupled to a first electrode, forming a mask on the surface of the first electrode exposing a predetermined zone of the first electrode, doping the first electrode through the mask, removing the mask from the surface of the first electrode, oxidizing the first electrode to form a layer of oxide over the first electrode with a thicker layer of oxide over the predetermined zone and a thinner layer of oxide elsewhere, forming at least one electrode over the first electrode on the thinner layer of oxide outside of the zone and forming at least one other electrode over the first electrode on the thicker layer of oxide inside the zone, whereby the one electrode and the other electrode have substantially different capacitive coupling to the electrode.

Abstract: A method for forming MOSFET devices, with reduced exposure to source and drain leakage currents due to punchthrough phenomena, has been developed. The structure is fabricated using a buried insulator sidewall to isolate the source and drain regions. This in turn is accomplished by creating a trench in the substrate, between the source and drain regions, and forming an insulator sidewall on the sides of the trench. A selective epitaxial process is used to refill the trench and a gate oxide is grown from the epitaxial silicon. Conventional processing completes this buried insulator MOSFET structure.

Abstract: A method is desired for making an array of dynamic random access memory (DRAM) cells having stacked capacitors with increased capacitance. The method involves forming a bottom electrode having a lower and upper fin-shaped portion in which a vertical extension is formed on the lower fin-shape portion at the same time that the upper fin is formed. This increases the capacitance of the stacked capacitor. The bottom electrode is formed by patterning a thick expendable silicon oxide layer and an underlying doped polysilicon layer (lower fin portion). Another polysilicon layer (upper fin portion is conformally coated over the thick insulating layer and patterned with an etch mask, which is smaller than the patterned insulating layer. An anisotropic etch is performed that forms the upper fin portion, the vertical extension on the lower fin portion and electrically isolates the array of electrodes.

Abstract: A method for forming an interconnect structure within a semiconductor device. An isolation region which defines an active region is formed upon a semiconductor substrate. A gate electrode is formed upon the active region and an interconnect is formed partially upon the active region and partially upon the isolation region. A low dose ion implant is then provided into the active region not covered by the gate or the interconnect. A pair of insulator spacers are then formed at opposite edges of the gate. A source/drain electrode is then formed within the active region between the gate electrode and the interconnect, and a second source/drain electrode is formed within the active region between the isolation region and the gate. Finally, a metal silicide layer is formed bridging adjoining surfaces of the interconnect and the first source/drain electrode. In a second embodiment, the source/drain electrodes are formed after the metal silicide layer.

Abstract: A method of forming doped well regions for FETs and doped field regions for channel stops to prevent surface inversion under the field oxide was achieved using a single ion implantation. The method involves forming a patterned silicon oxide layer over the field regions by selective deposition using liquid phase deposition (LPD) and a patterned photoresist mask. An ion implantation through the thick LPD silicon oxide layer over the field regions and through a thinner silicon nitride layer over the well regions resulted in a shallow doped field region and a deep doped well region. After removing the LPD oxide in HF, LOCOS was used to form the field oxide drive-in the dopant and anneal out the implant damage. After removing the silicon nitride layer over the well regions, gate oxides, polysilicon gate electrodes, and source/drains areas are formed to complete the FETs. The LPD process resulted in a doped field region self-aligned to a doped well region that required fewer masking and implant steps.