Methods of making a semiconductor memory device
First Claim
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1. A method for making a semiconductor memory device, the method comprising:
- providing a semiconductor substrate;
forming shallow-trench-isolations in the semiconductor substrate;
forming floating bodies and a base substrate out of the semiconductor substrate by removing portions of the semiconductor substrate and the shallow-trench-isolations, the floating bodies each being a disconnected portion of the semiconductor substrate held separate from the base substrate by portions of the shallow-trench-isolations which were not removed;
forming a conductive layer between the floating bodies and the base substrate; and
forming MOS transistors each including one of the floating bodies,wherein the floating body of each of the MOS transistors is adapted to store a data bit during operation of the memory device.
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Abstract
One-transistor (1T) capacitor-less DRAM cells each include a MOS transistor having a bias gate layer that separates a floating body region from a base substrate. The MOS transistor functions as a storage device, eliminating the need of the storage capacitor. Logic “1” is written to and stored in the storage device by causing majority carriers (holes in an NMOS transistor) to accumulate and be held in the floating body region next to the bias gate layer, and is erased by removing the majority carriers from where they are held.
226 Citations
15 Claims
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1. A method for making a semiconductor memory device, the method comprising:
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providing a semiconductor substrate; forming shallow-trench-isolations in the semiconductor substrate; forming floating bodies and a base substrate out of the semiconductor substrate by removing portions of the semiconductor substrate and the shallow-trench-isolations, the floating bodies each being a disconnected portion of the semiconductor substrate held separate from the base substrate by portions of the shallow-trench-isolations which were not removed; forming a conductive layer between the floating bodies and the base substrate; and forming MOS transistors each including one of the floating bodies, wherein the floating body of each of the MOS transistors is adapted to store a data bit during operation of the memory device. - View Dependent Claims (2, 3, 4, 5)
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6. A method for making a semiconductor memory device, the method comprising:
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providing a semiconductor substrate; forming isolation regions in the semiconductor substrate; forming floating bodies and a base substrate out of the semiconductor substrate by removing portions of the semiconductor substrate and the isolation regions, the floating bodies each being a disconnected portion of the semiconductor substrate held separate from the base substrate by portions of the isolation regions which were not removed; forming conductive material between the floating bodies and the base substrate; and forming field effect transistors each including one of the floating bodies. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification