Texas Instruments Corporation

Yin Hu

Theodore Warren Houston

William F Richardson

Amitava Chatterjee

Somnath S Nag

Keith Alan Joyner

Dirk N Anderson

Jarvis Benjamin Jacobs

Jeffrey A McKee

Ih-Chin Chen

Peter S McAnally

Iqbal Ali

Steve Hsia

Agerico L Esquirel

A method to simplify the polycide gate structure fabrication processes by using a hardmask to define a pattern of siliciding a silicon layer and then using the silicide to mask removal of the unreacted silicon and in locations where the hardmask had been present. The metal silicide formed in the exposed silicon regions and functions as a self-aligned mask against the silicon and etching. By using a selective etching process between the silicon and and the silicide , the silicon and can be etched down to the gate oxide to form the polycide (silicide/polysilicon) gate. The polycide gate formed by this method is particularly advantageous in DRAM applications, but can also be used as a MOS gate in a transistor.

Self-aligned stack formation

A method of fabricating a semiconductor device and the device which includes initially providing a layer of silicon having a thin oxide layer thereon and a patterned layer of a masking material not permeable to at least selected oxygen-bearing species and having a sidewall disposed over said oxide layer to provide an exposed intersection of the masking material and the oxide layer. An oxygen-bearing species conductive path is then formed on the sidewall of the masking material extending to the exposed intersection for conducting the selected oxygen-bearing species. A sidewall layer of a material different from the conductive path is formed on the conductive path. An oxygen-bearing species is then applied to the exposed intersection through the path and a thick oxide surrounding the masking material is fabricated concurrently or as a separate step. The masking material is preferably silicon nitride, the path is preferably silicon oxide and the sidewall layer is preferably silicon nitride.

Oxide profile modification by reactant shunting

An improved method for forming a DRAM chip is disclosed. According to this method, a memory cell gate is deposited in a memory cell array area of the DRAM chip. The memory cell gate overlies a first channel area of a substrate. A peripheral gate is deposited in a peripheral area of the DRAM chip. The peripheral gate overlies a second channel area of the substrate. A first dopant is implanted with a first concentration in a first plurality of source and drain regions of the substrate lying predominantly outside the first and second channel areas of the substrate. A sidewall is then formed adjacent to the peripheral gate. Simultaneously, an insulating layer is formed over the memory cell array area of the DRAM chip. A second dopant is implanted with a second concentration in a second plurality of source and drain regions of the substrate within the peripheral area of the DRAM chip. The implant of the second dopant is blocked by the sidewall and the insulating layer. In one embodiment, the first and second dopants are the same, and the dopant concentration in the second plurality of regions is greater than the dopant concentration in the first plurality of regions. This method allows the formation of more heavily doped source and drain regions in the peripheral area of the DRAM chip while keeping the heavily doped regions separated from the channel regions. This reduces diffusion into the channel regions and allows a smaller design rule to be used.

DRAM chip fabrication method

A semiconductor over insulator transistor (100) includes a semiconductor mesa (36) formed over an insulating layer (34) which overlies a semiconductor substrate (32). Source and drain regions (66, 68) of a first conductivity type are formed at opposite ends of the mesa. A body node (56) of a second conductivity type is located between the source and drain regions in the mesa. A gate insulator (40) and a gate electrode (46) lie over the body node. Halo implants (54, 56) are placed to completely separate the source and drain regions from the body node, or channel regions, for improving short channel effect. The transistor is useful as a pass gate and as a peripheral transistor in a DRAM, and also is useful in digital and analog applications and in low power applications.

Semiconductor on silicon (SOI) transistor with a halo implant

A technique of producing a semiconductor device or integrated circuit produces a planarized refill layer which has a more uniform thickness after etch back. In a silicon-on-insulator (SOI) device, dummy active areas are inserted between the active areas in order to maintain the thickness of the refill layer between the mesas to insure proper isolation between the active devices. The technique is also applicable to non-SOI devices.

Increasing uniformity in a refill layer thickness for a semiconductor

A technique of producing a semiconductor device or integrated circuit produces a planarized refill layer which has a more uniform thickness after polishing, such as by chemical-mechanical polishing (CMP). Dummy active areas are inserted between active areas in that portion of the substrate which would normally be occupied by a field oxide in order to reduce to 'dishing' that occurs during CMP in these areas. The dummy active areas can take the shape of a large block, a partially or completely formed ring structure or a plurality of pillars the area density of which can be adjusted to match the area density of the active areas in that region of the substrate. The design rule for the pillars can be such that no pillars are placed where polycrystalline silicon lines or first level metallization lines are to be placed in order to avoid parasitic capacitances.

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Plano, TX, United States of America

Yin Hu