Texas Instruments Corporation

Pradeep L Shah

Manzur Gill

Dave J McElroy

John Frederic Schreck

David J McElroy

Clyde R Fuller

Memory cell transistors are provided in which column structures (12a, 14a) are formed at the face of a semiconductor substrate (10). Floating gates (46) and control gates (52) are formed adjacent to the column structures (12a, 14a). The floating gates (46) and control gates (52) are insulatively disposed by gate oxide layer (42) and insulating layer (50). Source regions (36) are implanted in the semiconductor substrate. Drain regions (38) are also implanted in the column structures (12a, 14a).

Three dimensional FAMOS memory devices

A CMOS memory cell array and a method of forming it, which avoids problems caused by field oxide corner-rounding. A moat pattern defines alternating columns of active areas and field oxide regions. A source line pattern defines rows of source lines. Silicon dopant is implanted in areas not covered by the source line pattern to form buried n+ source lines. The field oxide regions are formed in areas not covered by the moat pattern. Subsequent fabrication steps may be in accordance with conventional CMOS fabrication techniques.

Memory cell array having continuous-strip field-oxide regions

Memory cell transistors are provided in which pillar structures or column structures (12, 12a, 14, and 14a) are formed at the face of a semiconductor substrate (10). Floating gates (46) and control gates (52) are formed adjacent to the pillar structures or column structures (12, 12a, 14, and 14a). The floating gates (46) and control gates (52) are insulatively disposed by gate oxide layer (42) and insulating layer (50). Source regions (36, 40, and 48) are implanted in the semiconductor substrate (10). Drain regions (38) are also implanted in the pillar structures or column structures (12, 12a, 14 and 14a).

Three dimensional famos memory devices and methods of fabricating

A CMOS memory cell array, and a process for making it, that avoids problems caused by LOCOS isolation of cells. Moats are formed by etching away columns of a thick field oxide layer. The moats have two-tiered sidewalls, such that an upper tier is sloped, and a lower tier is more vertical. This approach provides the advantages of sloped sidewalls, but avoids filament problems. After the moats are formed, subsequent fabrication steps may be in accordance with conventional fabrication techniques for CMOS arrays.

MOSFET cell array

CMOS memory cell array

A nonvolatile memory has pairs of cells in which each cell includes a control gate, a floating gate and a source/drain diffusion. A first cell in each of the pairs is producible to have one value of floating-gate to diffusion capacitance. A second cell in each of the pairs is producible to have a second value of floating-gate to diffusion capacitance different from the first value. The memory includes a first circuit for applying a first erasing pulse to the control gates and the diffusions of the first cells of the pairs and includes a second circuit for applying a second erasing pulse to the control gates and the diffusions of the second cells of the pairs. The first erasing pulse is adjustable to have a different magnitude than the second erasing pulse in order to narrow the margin of erased threshold voltages and thereby compensate for misalignment.

EEPROM array with narrow margin of voltage thresholds after erase

Silicon solar cells may be made from either 'P' type substrates with 'N' type dopants to form the geometries or with 'N' type substrates and 'P' type dopants forming the junction. This invention relates to the dopant species employed, the improved method of application and junction formation, formation of insitu anti-reflective coatings, and improved metallization processing for silicon solar cells. The invention does not affect preparation of the silicon substrate prior to diffusion steps, and is applicable both to planar solar cells and to vertical-multijunction cells. This invention discloses an alternate process of junction formation using arsenic as dopant. The process is uniquely different in the fact that it simplifies the number of process steps by using the doped oxide for junction formation, metallization mask and as an anti-reflection surface layer.

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Dallas, TX, United States of America

Pradeep L Shah