Abstract:
A method of erasing a flash electrically erasable read only memory (EEPROM) device composed of a plurality of memory cells (10) includes pre-programming (100) the plurality of memory cells (10), applying an erase pulse (110) to the plurality of memory cells (10) followed by an erase verification (120). The erase verification (120) is followed by soft programming (135) any memory cells having a threshold voltage below a predetermined minimum level (V TMIN ) and applying a positive gate stress (130) to the plurality of memory cells (10). The erase method prevents overerasing and provides a tightened threshold voltage distribution.
Abstract:
A dielectric memory cell (10) comprises a substrate (12) which includes a source region (18), a drain region (20), and a channel region (22) positioned therebetween. A multilevel charge trapping dielectric (14) is positioned on the surface of the substrate (12) and a control gate (16) is positioned on the surface of the dielectric and is positioned over the channel region (22). The multilevel charge trapping dielectric (14) includes a tunneling dielectric (14a) adjacent to the substrate (12), a high dielectric constant capacitive coupling dielectric (14c) adjacent to the control gate (16), and a charge trapping dielectric layer (14b) positioned therebetween.
Abstract:
A method of storing a data pattern and reproducing the data pattern within an array 30 of memory cells 48, which includes active columns 45b and 45g and inactive columns 46c and 45f, comprises storing the data pattern within the active columns 45b and 45g. An inactive memory cell programming pattern 32 is identified. The inactive memory cell programming pattern 32 identifies all, or a selected plurality, of the memory cells 48 in the inactive columns 45c and 45f in which a charge is to be stored for the purpose of periodically storing a charge in such memory cells 48 to prevent over erasure, during bulk erase, and leakage to active memory cells 48.
Abstract:
A method of overerase correction of a multi-bit memory cell by applying (424) a soft programming pulse having a ratio of Vg/Vd≥2 to overease bits.
Abstract:
A memory semiconductor cell (30) comprises a gate region (16), a source region (14) and a drain region (14). A channel region (17) is formed between the source region (14) and the drain region (14). The channel region (17) comprises a first channel portion (33) with a first concentration of doping material, the first channel portion (33) disposed adjacent to an edge of the channel region (17) closest to and substantially parallel to the gate region (16). The channel region (17) further comprises a second channel portion (31) with a second concentration of doping material, the second channel portion (31) disposed substantially parallel to the first channel portion (33) and a third channel portion (32), disposed between the first channel portion (33) and the second channel portion (31), with a third concentration of doping material. The third concentration is lower than the first concentration and lower than the second concentration. The memory cell may be one of two general types of non-volatile memory, a floating gate cell or a nitride read only memory (NROM), whereby layer (12B) in a floating gate or a nitride layer respectively.
Abstract:
A technique for forming at least part of an array of a dual bit memory core is disclosed. Initially, a portion of a charge trapping dielectric layer (608) is formed over a substrate (602) and a resist (614) is formed over the portion of the charge trapping dielectric layer (608). The resist (614) is patterned and a pocket implant (630) is performed at an angle to establish pocket implants (620) within the substrate (602). A bitline implant (634) is then performed to establish buried bitlines (640) within the substrate (602). The patterned resist is then removed and the remainder of the charge trapping dielectric layer (608) is formed. A wordline material (660) is formed over the remainder of the charge trapping dielectric layer and patterned to form wordlines (662) that overlie the bitlines (640). The pocket implants (620) serve to mitigate, among other things, complementary bit disturb (CBD) that can result from semiconductor scaling. As such, semiconductor devices can be made smaller and increased packing densities can be achieved by virtue of the inventive concepts set forth herein.
Abstract:
The present invention is a method and system for erasing a nitride memory device. In one embodiment of the present invention, an isolated P-well (510) is formed in a semiconductor substrate (529). A plurality of N-type impurity concentrations (550, 555) are formed in the isolated P-well (510) and a nitride memory cell (560) is fabricated between two of the N-type impurity concentrations (550, 555). Finally, an electrical contact (590) is coupled to the isolated P-well (510).
Abstract:
An array (40) of dual bit dielectric memory cells (48) comprises a plurality of bit lines. A first bit line (201) forms a source region for each of a plurality of memory cells (38) within a column of memory cells within the array (40). A second bit line (202) forms a drain region for each of the plurality of memory cells (38) within the column. A channel region (50) of the opposite conductivity is positioned between the first bit line (201) and the second bit line (202) and forms a junction with each. A selected word line (211) is positioned over the channel region (50) and forms a gate (60) over each for a plurality of memory cells (48) within a same row. A plurality of non-selected word lines (210, 212), are each parallel to the selected word line (211) and each form a gate (60) over one of the plurality of memory cells (48) within the column other than the selected one of the plurality of memory cells (49). A word line control circuit (46) applies a positive programming voltage (220) to the selected word line (211) while a bit line control circuit (44) simultaneously applies a positive drain voltage to the drain bit line (202) and a positive source voltage to the source bit line (201), the positive source voltage being less than the positive drain voltage.
Abstract:
A method of detecting a charge stored on a charge storage region (62) of a first dual bit dielectric memory cell (49) within an array (40) of dual bit dielectric memory cells (48) comprises coupling a first bit line (201) that forms a source junction with a channel region (50) of the first memory cell (49) to ground (68). A high voltage is applied to a gate (60) of the first memory cell (49) and to a second bit line (202) that is the next bit line to the right of the first bit line (201) and separated from the first bit line (201) only by the channel region (50). A third bit line (203), that is the next bit line to the right of the second bit line (202), is isolated such that its potential is effected only by its junctions with the a second channel region (50) and a third channel region (50) on opposing sides of the third bit line (203). A high voltage is applied to a pre-charge bit line that is to the right of the third bit line (203) and current flow is detected at the second bit line (202) to determine the programmed status of a source bit (62) of the first memory cell (49).
Abstract:
A method of storing a data pattern and reproducing the data pattern within an array 30 of memory cells 48, which includes active columns 45b and 45g and inactive (e.g. defective) columns 45c and 45f, comprises storing the data pattern within the active columns 45b and 45g. An inactive memory cell programming pattern 32 is identified. The inactive memory cell programming pattern 32 identifies all, or a selected plurality, of the memory cells 48 in the inactive columns 45c and 45f in which a charge is to be stored for the purpose of periodically storing a charge in such memory cells 48 to prevent over erasure, during bulk erase, and leakage to active memory cells 48.