Abstract: The objects of the present invention are accomplished by merging a MOS-FET device and a floating gate into a three dimensional trench structure. The trench device cell has four vertical sides and bottom. The bottom of the trench forms the channel region of the transfer FET of the EEPROM cell. The heavily doped source and drain regions are formed on two vertical sidewalls of the trench and oppositely face each other. The heavily doped regions cover the entire sidewall and have a depth which is greater than the trench depth so that the channel region is defined by the bottom of the trench. The remaining two vertical sidewalls of the trench are formed by isolation oxide. A first silicon dioxide layer covers the bottom of the trench and forms part of the gate oxide of the cell device. A second silicon dioxide layer covers the vertical sidewalls of the trench. The second silicon dioxide layer is relatively thin with respect to the gate oxide layer.

Abstract: The present invention is directed to a one-transistor non-volatile DRAM cell having a two layer floating gate to allow the contents of a storage capacitor to be transferred to the floating gate during power interruptions. The first layer of the floating gate is separated from a storage node of the storage capacitor by a tunnel oxide to allow electron tunnelling between the floating gate and the storage capacitor. In another embodiment of the present invention, a dual electron injector structure is disposed between a one layer floating and the storage node to allow electrons to be injected between the floating gate and the storage node. In another embodiment of the present invention, an erase gate is implemented to remove the charge on the floating gate. The erase gate can be separated from the floating gate by a tunnel oxide or a single electron injector structure to allow electrons to travel from the floating gate to the erase gate.

Abstract: The present invention is directed to a one-transistor non-volatile DRAM cell having a two layer floating gate to allow the contents of a storage capacitor to be transferred to the floating gate during power interruptions. The first layer of the floating gate is separated from a storage node of the storage capacitor by a tunnel oxide to allow electron tunnelling between the floating gate and the storage capacitor. In another embodiment of the present invention, a dual electron injector structure is disposed between a one layer floating and the storage node to allow electrons to be injected between the floating gate and the storage node. In another embodiment of the present invention, an erase gate is implemented to remove the charge on the floating gate. The erase gate can be separated from the floating gate by a tunnel oxide or a single electron injector structure to allow electrons to travel from the floating gate to the erase gate.

Abstract: The objects of the present invention are accomplished by merging a MOSFET device and a floating gate into a three dimensional trench structure. The trench device cell has four vertical sides and bottom. The bottom of the trench forms the channel region of the transfer FET of the EEPROM cell. The heavily doped source and drain regions are formed on two vertical sidewalls of the trench and oppositely face each other. The heavily doped regions cover the entire sidewall and have a depth which is greater than the trench depth so that the channel region is defined by the bottom of the trench. The remaining two vertical sidewalls of the trench are formed by isolation oxide. A first silicon dioxide layer covers the bottom of the trench and forms part of the gate oxide of the cell device. A second silicon dioxide layer covers the vertical sidewalls of the trench. The second silicon dioxide layer is relatively thin with respect to the gate oxide layer.