High coupling ratio split gate memory cell
First Claim
1. A non-volatile memory (NVM) cell, comprisinga substrate, the substrate including a surface substrate and a bulk substrate separated by an insulator layer;
- a split gate transistor disposed on the substrate, the split gate transistor including a first gate and a second gate separated by an intergate dielectric; and
a back gate in a surface portion of the bulk substrate adjacent to the insulator layer, the back gate serving as a back gate terminal of the NVM cell and coupled to back gate bias voltage (VBG).
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Accused Products
Abstract
A split gate non-volatile memory (NVM) cell formed on a crystalline-on-insulator (COI) substrate, such as a fully or partially depleted silicon-on-insulator (SOI) substrate is disclosed. The split gate memory cell includes a split gate disposed on a surface substrate of the SOI substrate between source/drain (S/D) regions. The split gate includes a storage gate with a control gate (CG) over a floating gate (FG), and a select gate (SG). A back gate is provided on the bulk substrate below a buried oxide (BOX). The back gate may be doped with the same polarity type dopants as the S/D regions. The back gate is coupled to the CG to increase CG coupling ratio, improving programming performance. Alternatively, the back gate may be doped with the opposite polarity type dopants as the S/D regions. The back gate is coupled to a negative bias during program and erase operations. The negative bias increases the gate threshold voltages of the SG and CG, resulting in higher electron generation efficiency to improve programming speed as well as a higher electric field to increase erase speed.
28 Citations
23 Claims
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1. A non-volatile memory (NVM) cell, comprising
a substrate, the substrate including a surface substrate and a bulk substrate separated by an insulator layer; -
a split gate transistor disposed on the substrate, the split gate transistor including a first gate and a second gate separated by an intergate dielectric; and a back gate in a surface portion of the bulk substrate adjacent to the insulator layer, the back gate serving as a back gate terminal of the NVM cell and coupled to back gate bias voltage (VBG). - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of forming a non-volatile memory (NVM) cell, comprising:
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providing a substrate, the substrate includes a surface substrate and a bulk substrate separated by an insulator layer; forming a split gate transistor disposed on the substrate, wherein forming the split gate transistor includes forming a first gate adjacent to a second gate and separated by an intergate dielectric; and forming a back gate in a surface portion of the bulk substrate adjacent to the insulator layer, wherein the back gate serves as a back gate terminal of the NVM cell and is coupled to back gate bias voltage (VBG). - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A device comprising:
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a substrate, the substrate includes a surface substrate and a bulk substrate separated by an insulator layer; a plurality of non-volatile memory (NVM) cells on and in the substrate, the NVM cells interconnected in a row direction and a column direction to form a memory array with rows and columns of the NVM cells, wherein each of the NVM cell includes; a split gate transistor disposed on the substrate, the split gate transistor disposed between first and second source/drain (S/D) regions, wherein the split gate transistor includes a select gate (SG) and a storage gate separated by an intergate dielectric, and a back gate in a surface portion of the bulk substrate adjacent to the insulator layer, wherein the back gate serves as a back gate terminal of the NVM cells and is coupled to back gate bias voltage (VBG); the NVM cells od each row are interconnected by a control gate line (CGL) coupled to control gate (CG) terminals of a respective row of the NVM cells and a select gate line (SGL) coupled to select gate (SG) terminals of a respective row of the NVM cells; and the NVM cells of each column are interconnected by a source line (SL) coupled to source terminals of a respective column of the NVM cells and a bitline (BL) coupled to drain terminals of a respective column of the NVM cells. - View Dependent Claims (16, 17, 18, 19)
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20. A device comprising:
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a plurality of non-volatile memory (NVM) cells, wherein the NVM cells are interconnected in a row direction and a column direction to form a memory array with rows and columns of the NVM cells, and wherein the NVM cells are disposed in and on a substrate, the substrate includes a surface substrate and a bulk substrate separated by an insulator layer; the NVM cells of each row are interconnected by a control gate line (CGL) coupled to control gate (CG) terminals of a respective row of the NVM cells and a select gate line (SGL) coupled to select gate (SG) terminals of a respective row of the NVM cells; the NVM cells of each column are interconnected by a source line (SL) coupled to source terminals of a respective column of the NVM cells and a bitline (BL) coupled to drain terminals of a respective column of the NVM cells; and each of the NVM cells includes a back gate coupled to its respective CGL. - View Dependent Claims (21, 22, 23)
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Specification