Abstract: A plasma dry etch process for trench etching in single slice RIE etch reactors wherein a selective sidewall passivation is accomplished to control the profile of the trench being etched. The process comprises methods of passivating the sidewall by passivation on a molecular scale and by passivation by a veneer type passivation comprising buildup of a macroscopic residue over the surface of the sidewall. Several methods are disclosed for forming and shaping the passivating layers (both mono-atomic and bulk). By carefully controlling the composition and shape of the sidewall passivating veneer in conjunction with other etch factors, the desired trench profiles can be achieved.

Abstract: The disclosure relates to the formation of reachup contacts for VLSI integrated circuit interconnects wherein studs are formed of a conducting material which reaches up through subsequently applied insulating films or the like to contact metal patterns. The reachup contacts are fabricated using LPCVD polycrystalline silicon as a refill in etched apertures in an insulating layer with a titanium or other appropriate material over the silicon layer with subsequent reaction of the silicon layer and the titanium layer to form temperature resistant studs of titanium silicide.

Abstract: An EEPROM cell is described which includes a trench formed in the field oxide adjacent to the EEPROM cell. Both the control gate and the floating gate of the cell are formed over this trench. By forming both gates above the trench, the capacitive coupling between the gates is increased. Thus a EEPROM cell constructed in accordance with the teachings of this invention may be constructed using a smaller surface area of the integrated circuit or may utilize a smaller programming voltage to charge and discharge the floating gate.

Abstract: A dRAM cell and array of cells, together with a method of fabrication, are disclosed wherein the cell includes one field effect transistor and one storage capacitor with the capacitor formed in a trench in a substrate and the transistor channel formed by epitaxial growth on the substrate. The transistor source and drain are insulated from the substrate, and the transistor may be adjacent the trench or on the upper portion of the trench sidewalls. Signal charge is stored on the capacitor plate insulated from the substrate.

Abstract: In one embodiment of a vertical bipolar transistor constructed in accordance with the teachings of this invention, oxygen is implanted into the vertical bipolar transistor to provide a silicon dioxide layer between the base and collector of the vertical bipolar transistor. This silicon dioxide layer reduces the actual interface area of the base to collector junction, thereby decreasing the capacitance of the base-collector junction. In addition, the dielectric constant of the silicon dioxide layer is such that the capacitance across the silicon dioxide layer, and thus between the base and collector, is minimal relative to the base to collector capacitance provided by the base to collector junction itself. In an alternative embodiment, nitrogen is implanted to form silicon nitride regions rather than silicon dioxide regions.

Abstract: A plasma dry etch process for etching deep trenches in single crystal silicon material with controlled wall profile, for trench capacitors or trench isolation structures. HCl is used as an etchant under RIE conditions with a SiO2 hard mask. The SiO2 hard mask is forward sputtered during the course of the Si etch so as to slowly deposit SiOx (x<2) on the sidewalls of the silicon trench. Since the sidewall deposit shadows etching at the bottom of the trench near the sidewall, the effect of this gradual buildup is to produce a positively sloped trench sidewall without "grooving" the bottom of the trench, and without linewidth loss. This process avoids the prior art problems of mask undercut, which generates voids during subsequent refill processing, and grooving at the bottom of the trench, which is exceedingly deleterious to thin capacitor dielectric integrity.

Abstract: The dielectric between the floating gate and the control gate, in an EEPROM or other floating gate memory is made by forming an oxide/nitride stack over the (first polysilicon) control gate. This dielectric not only provides a very high specific capacitance, which is desired to provide tight coupling of the control to the floating gate, but also provides excellent dielectric integrity. Moreover, the thickness of this dielectric layer does not exhibit any uncontrolled increase during exposure to second gate oxidation. Thus, the polysilicon-to-polysilicon dielectric is not only of high specific capacitance and high integrity, it is also very uniform.

Abstract: A micropackage for providing high density, three dimensional packaging of integrated circuit chips. A chipmount (10) includes a plurality of channels (36) on the bottom surface thereof for holding a corresponding plurality of integrated circuit chips (16). A shallow cavity (34) is formed on the top surface of the chipmount (10) for holding another integrated circuit (14). Metallization interconnections (22) are formed on the top and bottom surfaces of the chipmount (10) and are terminated by solder pads (24, 39). Conductive conduits (26) are formed through the chipmount (10) for providing electrical continuity between an integrated circuit chip (14) mounted on the top side, to other integrated circuit chips (16) mounted on the bottom side of the chipmount. Other conductive conduits (30, 32) and a bridging member (28) insulates intersecting conductive paths (48, 50). The micropackage is fabricated with standard silicon technology.

Abstract: A cap oxide (or oxide/nitride) prevents silicon outdiffusion during the reaction step which forms direct-react titanium silicide.

Abstract: A current source MOSFET is fabricated by forming a trench (36) in an n++ drain (source) region (32) and extending below the trench (36). A gate oxide layer (40) is disposed on the sidewalls of the trench (36) and a conductive region (38) formed in the bottom of the trench (36). A gate-to-source (gate-to-drain) contact (49) is then formed in the trench (36) and then a drain (source) contact (58) formed. The vertical gate structure defines a vertical channel region on all sides of the trench (36) to allow a wider devive to be fabricated in a smaller overall silicon area.

Abstract: The present invention provides a structure and method for fabricating that structure which provides increased capacitance over the prior art while occupying a minimum of surface area of the integrated circuit. The present invention accomplishes this by interleaving multiple capacitor plates to provide increased capacitance while occupying the same surface area as a prior art capacitor providing a fraction of the capacitance provided by the present invention. The present invention is fabricated by providing a capacitor stack which includes interleaved plates of material which may be selectively etched and which is separated by appropriate dielectric material. One portion of the stack is masked while one set of the interleave plates is etched. The etched portion of the interleave plates is filled by a suitable dielectric and a contact is made to the remaining plates. A different portion of the stack is then exposed to an etch which etches the other set of interleave plates.

Abstract: Static random access memory having an edge-triggered power up architecture. Each element of the signal path is powered up only during the period when it is expected to be active. Separate delays are provided to tailor the delay of the power-up pulses for each separate circuit component, and separate 1-shot pulse generators, with the pulse width tailored to the power-up duration required by each circuit element, are provided for each circuit element.

Abstract: A dRAM cell and array of cells, together with a method of fabrication, are disclosed wherein the cell includes one field effect transistor and one storage capacitor with both the transistor and the capacitor formed in a trench in a substrate. The transistor source, channel, and drain and one capacitor plate are formed in a layer of material inserted into the trench and insulated from the substrate; the gate and other capacitor plate are formed in the substrate trench sidewall. In preferred embodiments bit lines on the substrate surface connect to the inserted layer, and word lines on the substrate surface are formed as diffusions in the substrate which also form the gate. The trenches and cells are formed in the crossings of bit lines and word lines; the bit lines and the word lines form perpendicular sets of parallel lines.

Abstract: One embodiment of the present invention provides a method whereby a symmetrical transistor may be fabricated which eliminates the problems of scalability caused by the requirement of fabricating an extrinsic base. The method accomplishes this by the use of a polysilicon extrinsic base structure which is formed in a trench containing an insulating layer in the bottom of the trench formed by differential oxidation.After fabricating appropriate isolation structures, two trenches for either side of the intrinsic base are cut into the surface of the substrate. The bottom of these trenches are then heavily doped. A silicon dioxide layer is then thermally grown in the trenches. Because the bottoms of the trenches are heavily doped, a thicker silicon dioxide layer is formed in the bottom of the trenches. This silicon dioxide layer is then etched so that the silicon dioxide layer is completely removed from the sides of the trench but remains in the bottoms of the trench.

Abstract: DRAM cells and arrays of cells on a semiconductor substrate, together with methods of fabrication, are disclosed wherein the cells are formed in pairs or quartets by excavating a trench or two trenches through the cell elements to split an original cell into two or four cells during the fabrication. The cells include vertical field effect transistors and capacitors along the trench sidewalls with word lines and bit lines crossing over the cells.

Abstract: A process is disclosed for fabricating N-wells in a P-type substrate. An N-type epitaxial layer is formed on the surface of a P+ substrate. The N-type epitaxial layer is then masked and a doubly charged boron implant is performed on the exposed areas of the N-type epitaxial layer. Because of the lower mass of boron, a common production 200 kiloelectron volt implanter provides sufficient implantation energy to doubly charged boron to provide a P region which extends through the N-type epitaxial layer. The remaining N-type portions of the epitaxial layer provide N-wells for the fabrication of complementary field effect transistor circuitry.

Abstract: Using a structure according to one embodiment of the present invention, active elements in integrated circuitry may be completely isolated from other elements in the integrated circuitry by silicon dioxide regions surrounding the sides of the region containing the active element and a buried diffusion beneath the active element extending to all sides of the isolating silicon dioxide regions.In one embodiment of the present invention, an isolation structure is fabricated by etching a silicon substrate to remove the silicon from the entire region occupied by the isolated active area and the isolation structure of this embodiment of the invention. A conformal layer of silicon dioxide, or other dielectric material, is then deposited on the surface of the silicon substrate. The conformal silicon dioxide layer is then anisotropically etched to remove the silicon dioxide on the bottom of the isolation region but still provide a sidewall region of silicon dioxide on the sides of the isolation region.

Abstract: A dRAM cell and array of cells, together with a method of fabrication, are disclosed wherein the cell includes one field effect transistor and one capacitor with both the transistor and the capacitor formed in a trench in a substrate. One capacitor plate and the transistor source are common and are formed in the lower portion of the trench sidewall. The transistor drain is formed in the upper portion of the trench sidewall to connect to a bit line on the substrate surface, and the channel is the vertical portion of the trench sidewall between the source and drain. A ground line runs past the transistor gate in the upper portion of the trench down into the lower portion of the trench to form the other capacitor plate.

Abstract: One embodiment of the present invention provides a polycrystalline silicon loading device occupying a minimum of surface area in an integrated circuit. A very thin layer of silicon nitride is formed on the surface of a heavily doped contact point in the integrated circuit. An undoped layer of polycrystalline silicon is then formed on the surface of this thin layer of silicon nitride. A thin layer of silicon nitride is then formed on the surface of the undoped polycrystalline silicon layer. Finally a heavily doped polycrystalline silicon layer for making contact to the loading device is formed on the surface of the second thin silicon nitride layer. Because the two thin silicon nitride layers are very thin, tunneling current through the silicon nitride layers begins at a fairly low threshold level. After tunneling occurs, the main resistance element of the load device is the undoped polycrystalline silicon.

Abstract: A static random access memory wherein all cells have p-channel access transistors, p-channel driver transistors, and n-channel loads. The access transistors have a width to length ratio which is greater than the width to length ratio of the driver transistors.The bit lines are precharged close to VSS, and the wordlines are held near VCC in the off state. Thus the operating signals in the array of the SRAM of the present invention are opposite to those in SRAMs of the prior art.