Abstract:
A memory cell array (50) comprises a two dimensional array of memory cells (52) fabricated on a semiconductor substrate (54). The memory cells (52) are arranged in a plurality of rows defining a row direction (67) and a plurality columns defining a column direction (69). Each column of memory cells (52) comprising a plurality of alternating channel regions (58) and source/drain regions (64). A conductive interconnect (72) is positioned above each source/drain region (64) and coupled to only one other source/drain region (64). The one other source/drain region (64) is in a second column that is adjacent to the column. The conductive interconnects (64) are positioned such that every other conductive interconnect (64) connects to the adjacent column to a right side of the column and every other conductive interconnect connects to adjacent column to the left side of the column. A plurality of source/drain control lines (70) extends between adjacent columns of memory cells (52) and electrically couple to each conductive interconnect (72) that couples between the adjacent columns.
Abstract:
According to one exemplary embodiment, a method for fabricating a floating gate memory array comprises a step of removing (404) a dielectric material from an isolation region (110) situated in a substrate (258,358) to expose a trench (128,228), where the trench (128,228) is situated between a first source region (116,216,316) and a second source region (118,218), where the trench (128,228) defines sidewalls (150,250) in the substrate (258,358,). The method further comprises implanting (406) an N type dopant in the first source region (116,216,316), the second source region (118,218,318), and the sidewalls (150,250) of the trench (128,228), where the N type dopant forms an N+ type region (252,352). The method further comprises implanting (408) a P type dopant in the first source region (116,216,316), the second source region (118,218), and the sidewalls (150,250) of the trench (128,228), where the P type dopant forms a P type region (256,356), and where the P type region (256,356) is situated underneath the N+ type region (252,352).
Abstract:
A system and methodology is provided for programming first bit (CO, C2, C4, C6) and second bit (C1, C3, C5, C7) of a memory array (68) of dual bit memory cells (10, 82, 84, 86, 88) at a substantially high delta VT. The substantially higher VT assures that the memory array (68) will maintain programmed data and erase data consistently after higher temperature stresses and/or custumer operation over substantial periods of time. At a substantially higher delta VT, programming of the first bit (C0, C2, C4, C6) of the memory cell (10, 82, 84, 86, 88) causes the second bit (C1, C3, C5, C7) to program harder and faster due to the shorter channel (8) length. Therefore, the present invention employs selected gate and drain voltages and programming pulse widths during programming of the first bit (C0, C2, C4, C6) and second bit (C1, C3, C5, C7) that assures a controlled first bit VT and slows down programming of the second bit (C1,C3, C5, C7). Furthermore, the selected programming parameters keep the programming times short without degrading charge loss.
Abstract:
A lateral doped channel, particularly in a MOSFET of a semiconductor memory cell. A first doping material (210) is implanted substantially vertically into a region (220) adjacent to a gate structure. A diffusion process diffuses the first doping material into a channel region beneath the gate structure. A second doping material (240) is implanted substantially vertically into the region (220) adjacent to a gate structure. The second implantation forms source/drain regions (250) and may terminate the channel region. The channel region thus comprises a laterally non-uniform doping profile which beneficially mitigates the short channel effect and is highly advantageous as compensation for manufacturing process variations in channel length. The memory cell may be a floating gate type or a nitride type (SONOS) non-volatile memory.
Abstract:
A method of manufacturing a flash memory device in which minimal gate edge lifting is accomplished by minimally oxidizing the gate stack and exposed surface of the substrate, anisotropically etching the layer of oxide from the substrate, forming a doped solid source material on portions of the substrate in which source regions are to be formed and diffusing the dopants from the solid source material into the substrate.
Abstract:
A memory cell array (50) comprises a two dimensional array of memory cells (52) fabricated on a semiconductor substrate (54). The memory cells (52) are arranged in a plurality of rows defining a row direction (67) and a plurality columns defining a column direction (69). Each column of memory cells (52) comprising a plurality of alternating channel regions (58) and source/drain regions (64). A conductive interconnect (72) is positioned above each source/drain region (64) and coupled to only one other source/drain region (64). The one other source/drain region (64) is in a second column that is adjacent to the column. The conductive interconnects (64) are positioned such that every other conductive interconnect (64) connects to the adjacent column to a right side of the column and every other conductive interconnect connects to adjacent column to the left side of the column. A plurality of source/drain control lines (70) extends between adjacent columns of memory cells (52) and electrically couple to each conductive interconnect (72) that couples between the adjacent columns.
Abstract:
A method of manufacturing a flash memory device in which minimal gate edge lifting is accomplished by minimally oxidizing the gate stack and exposed surface of the substrate, anisotropically etching the layer of oxide from the substrate, forming a doped solid source material on portions of the substrate in which source regions are to be formed and diffusing the dopants from the solid source material into the substrate.
Abstract:
A memory cell array (50) comprises a two dimensional array of memory cells (52) fabricated on a semiconductor substrate (54). The memory cells (52) are arranged in a plurality of rows defining a row direction (67) and a plurality columns defining a column direction (69). Each column of memory cells (52) comprising a plurality of alternating channel regions (58) and source/drain regions (64). A conductive interconnect (72) is positioned above each source/drain region (64) and coupled to only one other source/drain region (64). The one other source/drain region (64) is in a second column that is adjacent to the column. The conductive interconnects (64) are positioned such that every other conductive interconnect (64) connects to the adjacent column to a right side of the column and every other conductive interconnect connects to adjacent column to the left side of the column. A plurality of source/drain control lines (70) extends between adjacent columns of memory cells (52) and electrically couple to each conductive interconnect (72) that couples between the adjacent columns.
Abstract:
A lateral doped channel, particularly in a MOSFET of a semiconductor memory cell. A first doping material (210) is implanted substantially vertically into a region (220) adjacent to a gate structure. A diffusion process diffuses the first doping material into a channel region beneath the gate structure. A second doping material (240) is implanted substantially vertically into the region (220) adjacent to a gate structure. The second implantation forms source/drain regions (250) and may terminate the channel region. The channel region thus comprises a laterally non-uniform doping profile which beneficially mitigates the short channel effect and is highly advantageous as compensation for manufacturing process variations in channel length. The memory cell may be a floating gate type or a nitride type (SONOS) non-volatile memory.
Abstract:
One aspect of the present invention relates to a method of making a flash memory cell (32), involving providing a substrate (30) having a flash memory cell (32) thereon; forming a self-aligned source mask (48) over the substrate, the self aligned source mask (48) having openings (50) corresponding to source lines; implanting a source dopant of a first type in the substrate through the openings (50) in the self-aligned source mask (48) corresponding to source lines (52); removing the self-aligned source mask (48) from the substrate (30); forming a MDD mask (54) over the substrate (30), the MDD mask (54) covering the source lines (52) and having openings (56) corresponding to drain lines; and implanting a medium dosage drain implant of a second type to form a drain region (58) in the substrate (30) adjacent the flash memory cell (32).