Abstract: Electrical interconnection with studs is formed by depositing conductive stud material in contact holes in a dielectric layer; patterning the conductive stud material and removing a shallow portion of the dielectric layer surrounding the stud material; depositing a thin layer of dielectric material over the conductive stud and first dielectric layer; forming a trench in the dielectric layers and over the top of the stud material; and depositing conductive material in the trench.

Abstract: A memory cell having a grooved gate formed in a sub-lithographic groove, and methods of making thereof are disclosed. The groove extends the channel length to include the groove sidewalls and width of the groove. Sidewall sections of the channel located along the gate sidewalls have a larger length than the bottom channel section length located along the gate bottom width. Thus, the memory device is primarily controlled by the sidewall channel sections, instead of the bottom channel section. The groove may be a stepped groove formed by a two step etch to further increase the channel length and may be formed centered along the gate conductor width.

Abstract: A buried plate particularly suitable for formation of a common plate of a plurality of trench capacitors, such as are employed in dynamic random access memories, is formed by implantation of impurities in one or more regions of a wafer or semiconductor layer, epitaxially growing a layer of semiconductor material over the implanted regions and diffusing the implanted impurities into the wafer or semiconductor layer and into the epitaxial layer. Diffusion from such a source avoids process complexity compared with provision of diffusion sources within capacitor trenches and further provides an impurity concentration profile which varies with depth within the resulting body of semiconductor material, resulting in a well-defined boundary of the buried plate and an isolation region both above and below the buried plate.

Abstract: A method of making electrical contacts to device regions in a substrate is taught. A first set of contacts are self-aligning and borderless and a second set of contacts are bordered. The method comprises the steps of providing a first insulating layer over the substrate and forming the first set of contacts in a self-aligned and borderless manner. This is followed by forming a second insulating layer over said first insulating layer, in which the second set of contacts that are bordered to the gate electrode and peripheral diffusions are formed through the first and second insulating layers. In addition, bordered contacts to the first set of borderless contacts are formed through the second insulating layer.

Abstract: A process for stripping thin layers of oxide such as sacrificial pad oxide employs etching chemistry that widens cracks to remove shallow cracks and limit the widening of deep cracks, thereby producing a final oxide surface on thick layers of oxide that is less rough than prior art methods and enabling the fabrication of oxide-filled trenches that have geometries and/or surface smoothness that were previously impossible.

Abstract: An SOI DRAM includes a direct body contact between the SOI layer and the silicon substrate, and field-shield isolation positioned on the surface of the SOI structure which extends over the direct body contact. Deep trench storage capacitors are positioned adjacent the direct body contact.

Abstract: Stringers and depth of focus problems in substrates having above-surface isolation schemes are avoided by applying a first portion of a gate conductor over the entire surface having above-surface isolation, selectively removing the gate conductor from above the isolation features of the above-surface isolation, and overcoating the entire surface with a second portion of gate conductor. The process has particular application to substrates that employ regions having field-shield isolation. An important feature of the invention is drawn to creating structures wherein gate conductor is applied to a substrate including both above-surface and below-surface isolation regions in a manner which leaves the gate conductor planarized over both the above-surface and below-surface regions.

Abstract: Integrated circuit structures of sub-lithography dimensions are formed by conformal deposition of alternating layers of materials having differing etch rates within an aperture over a body of material to be etched. One of the materials in the alternating layers is then selectively and preferentially etched to form a mask through which etching can be performed on the body of material to be etched. This technique is particularly suited to the formation of structurally robust capacitors for memory cells which have greatly increased plate area, resulting in increased capacitance, while maintaining a small footprint for the capacitor structure.

Abstract: An SOI deep-trench DRAM having body contacts and field shield isolation makes contact between the SOI device layer and a buried conductive layer below the insulating layer at selected sites between adjacent deep trench capacitors. The buried layer may be biased to provide better attraction for holes.

Abstract: An SOI deep-trench DRAM having body contacts and field shield isolation makes contact between the SOI device layer and the field shield layer at selected sites between adjacent deep trench capacitors. The field shield layer is biased negative to provide better isolation and to set the body potential of the array transistors.

Abstract: A high density substrate plate DRAM cell memory device and process are described in which a buried well region is formed adjacent to deep trench capacitors such that the substrate region of DRAM transfer FETs can be electrically isolated from other FETs on a semiconductor substrate. The buried region is partially formed by ion implantation and diffusion to intersect the walls of the deep trenches.

Abstract: A deep trench type DRAM cell with shallow trench isolation has a buried polysilicon strap that is defined without the use of a separate mask by depositing the strap material over at least the deep trench before shallow trench definition and using the shallow trench isolation mask to overlap partially the deep trench, thereby defining the strap during the process of cutting the shallow trench.

Abstract: A semiconductor memory device and operational method having reduced well noise are provided. The memory device includes a plurality of memory cells arranged in rows and columns within an array well and addressable by a plurality of word lines and bit lines. The array well is biased to a desired potential and a sense amplifier is employed to read bit line states during a predefined bit line signal development period. Array well biasing is removed during at least a portion of this signal development, so that the well potential floats (ideally remaining stable) as signals are being developed on the bit lines. This temporary, floating well technique is particularly important for open bit line architectures.

Abstract: Disclosed is a Dynamic Random Access Memory (DRAM) cell which includes a storage capacitor disposed in a trench formed in a semiconductor substrate and an access transistor disposed in a well which is opposite in conductivity type to that of the substrate and a buried oxide collar which surrounds an upper portion of the trench.

Abstract: A wordline driver circuit for reading the contents of a Dynamic Random Access Memory (DRAM). The circuit is implemented in CMOS and is capable of pulling the wordlines to a negative potential with respect to the substrate, thereby decreasing the access time. An NMOS pull-down transistor channel is implemented as a P-well within an N-well. Applying a negative potential to the source of the pull-down transistor permits the transistor to be switched so that a negative potential is applied to the wordline when the NMOS pull-down transistor is gated into conduction. A PMOS pull-up transistor is serially connected to the NMOS pull-down transistor drain, permitting the wordline to be driven positively.

Abstract: A high density substrate plate DRAM cell memory device and process are described in which a buried well region is formed adjacent to deep trench capacitors such that the substrate region of DRAM transfer FETs can be electrically isolated from other FETs on a semiconductor substrate. The buried region is partially formed by ion implantation and diffusion to intersect the walls of the deep trenches.

Abstract: The present invention is a self-aligned, vertical bipolar transistor structure and a method of manufacturing such a structure. Reducing lateral dimensions with optical lithography is difficult and not much is gained without concurrently reducing alignment tolerances. For bipolar transistors the alignment tolerance is particularly important since it determines the parasitic capacitances and resistances and thus directly affects speed. In this application a new fully self-aligned transistor structure is presented that self-aligns the shallow trench, extrinsic base contact, and the emitter polysilicon to the intrinsic device area. The structure has no critical alignments. To insure extrinsic-intrinsic base linkup the intrinsic base is put in early in the process, conserved during the stack etch, and patterned underneath the sidewall during the silicon mesa etch.

Abstract: A fabrication method for forming SOI structures where perfect material is grown epitaxially on a substrate and then, through a series of selective etches and oxidations, an insulating layer is formed below the epitaxial silicon. In the method, low temperature epitaxial techniques are employed to grow a layered structure including a first layer p++ silicon on a substrate wafer, a layer of intrinsic silicon is then formed on the first p++ silicon layer, and a second layer of p++ silicon is formed on the intrinsic silicon layer, and a finally a layer of p-silicon is fabricated on top of the second p++ silicon layer. Grooves are formed through the p-layer, the second p++ silicon layer, the intrinsic silicon layer, and stopped in the first p++ silicon layer. An etch is then employed to remove the intrinsic layer long enough for the p++ silicon layer to be totally undercut, leaving an air gap between the two p++ silicon layers.