Abstract:
PROBLEM TO BE SOLVED: To provide a dynamic random access memory formed at a semiconductor body comprising individual paired memory cell separated each other by a vertical electric isolation trench and separated from a support circuit. SOLUTION: An isolation trench 20, comprising a side wall, upper part, and lower part, encloses the region of a semiconductor body 10 comprising a memory cell. Thus, the paired memory cell is electrically separated each other, while separated from a support circuit which is not in the enclosed region but contained in the semiconductor body. The isolation trench lower-part is filled with a conductive material 14, which material comprises a side wall part which is at least partially separated from the trench lower-part side wall by a first electric insulator and a lower part electrically connecting to the semiconductor body. The isolation trench upper-part is filled with a second electric insulator.
Abstract:
PROBLEM TO BE SOLVED: To obtain necessary insulation between a capacitor for storage and a transistor in a memory cell, using both a capacitor for storage in a vertical trench and a vertical transistor. SOLUTION: One memory cell formed in a semiconductor main body 10 includes a polycrystalline silicon packing part 22 as a capacitor for storage and one field-effect transistor. This field-effect transistor includes a source 43 formed in the sidewall of a trench, a drain 42 formed in the semiconductor main body and provided with a surface in common with the upper face of the semiconductor main body, a channel region including both vertical and horizontal parts, and a polycrystalline silicon gate at the upper part of the trench. Thus, an insulating oxide layer 28 at the top end of the polycrystalline silicon packing part, which is useful as a storage node and the polycrystalline silicon packing part which is useful as a gate conductor can be obtained in this process for manufacturing.
Abstract:
A method of forming relatively thin uniform insulating collar in the storage trench of a storage trench DRAM cell. A DRAM trench is first formed in a silicon substrate. Then, a nitride liner (81) is deposited on the silicon trench walls. The nitride liner may be deposited directly on the silicon walls or on an underlying oxide layer (79). A layer of amorphous silicon (83) is then deposited over the nitride liner. A silicon nitride layer is deposited on the oxidized surface of the amorphous silicon. A resist (83) is formed in the lower portion of the trench, and the exposed silicon nitride layer on top of the amorphous silicon is removed, leaving the upper portion of the amorphous silicon layer exposed. The upper portion of the layer of amorphous silicon is then oxidized so as to form a relatively thin, uniform collar (89) along the entire circumference of the trench. The nitride liner underlying the amorphous silicon layer enhances the thickness uniformity of the amorphous silicon layer and thereby the uniformity of the resulting oxide collar. The nitride liner also acts to limit lateral oxidation of the silicon trench walls during oxidation of the amorphous silicon layer. The nitride liner underlying the collar is also effective in cell operation to control the cell charge at the collar-substrate interface.
Abstract:
A structure and process for semiconductor fuses and antifuses in vertical DRAMS provides fuses and antifuses in trench openings formed within a semiconductor substrate. Vertical transistors may be formed in other of the trench openings formed within the semiconductor substrate. The fuse is formed including a semiconductor plug (108) formed within an upper portion of the trench opening (110) and includes conductive leads (252, 254) contacting the semiconductor plug. The antifuse is formed including a semiconductor plug formed within an upper portion of the trench opening and includes conductive leads formed over the semiconductor plug, at least one conductive lead isolated from the semiconductor plug by an antifuse dielectric. Each of the fuse and antifuse are fabricated using a sequence of process operations also used to simultaneously fabricate vertical transistors according to vertical DRAM technology, the plug forming the gate of the vertical transistor.
Abstract:
A magnetic random access memory (MRAM) device includes a magnetic tunnel junction (MTJ) stack formed over a lower wiring level, a hardmask formed on the MTJ stack, and an upper wiring level formed over the hardmask. The upper wiring level includes a slot via bitline formed therein, the slot via bitline in contact with the hardmask and in contact with an etch stop layer partially surrounding sidewalls of the hardmask.
Abstract:
A DRAM memory cell and process sequence for fabricating a dense (20 or 18 square) layout is fabricated with silicon-on-insulator (SOI) CMOS technology. Specifically, the present invention provides a dense, high-performance SRAM cell replacement that is compatible with existing SOI CMOS technologies. Various gain cell layouts are known in the art. The present invention improves on the state of the art by providing a dense layout that is fabricated with SOI CMOS. In general terms, the memory cell includes a first transistor provided with a gate, a source, and a drain respectively; a second transistor having a first gate, a second gate, a source, and a drain respectively; and a capacitor having a first terminal, wherein the first terminal of said capacitor and the second gate of said second transistor comprise a single entity.