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Storage Cell for Electronically Alterable Read Only Storage Arrays Using Dual Electron Injector Structure Charge Injectors

IP.com Disclosure Number: IPCOM000053013D
Original Publication Date: 1981-Aug-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 3 page(s) / 41K

Publishing Venue

IBM

Related People

Young, DR: AUTHOR

Abstract

Two gates are used that are capacitatively coupled to the floating gate. As shown in Fig. 2, the control gate is used for selective reading and selective writing of a ``1''. The reset gate is used for blanket erasing to place all the cells in the ``0'' state. The ``0'' state has negative charge on the floating gate. This is accomplished by applying a positive voltage to the reset gate which is coupled to the floating gate, making it (the floating gate) go positive with respect to the control gate which is at zero potential. The voltage applied between the floating gate and the control gate is sufficient to induce a flow of electrons from the control gate to the floating gate, leaving the floating gate with a negative charge.

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Storage Cell for Electronically Alterable Read Only Storage Arrays Using Dual Electron Injector Structure Charge Injectors

Two gates are used that are capacitatively coupled to the floating gate. As shown in Fig. 2, the control gate is used for selective reading and selective writing of a ``1''. The reset gate is used for blanket erasing to place all the cells in the ``0'' state. The ``0'' state has negative charge on the floating gate. This is accomplished by applying a positive voltage to the reset gate which is coupled to the floating gate, making it (the floating gate) go positive with respect to the control gate which is at zero potential. The voltage applied between the floating gate and the control gate is sufficient to induce a flow of electrons from the control gate to the floating gate, leaving the floating gate with a negative charge.

Selective writing of a ``1'' on the cell is accomplished using the control gate for X selection and the source and drain diffusions for Y selection. The X line for the selected cell has a positive voltage applied. This voltage induces an electron current to flow from the floating gate to the control gate, leaving the floating gate either discharged or with a positive charge depending on the amplitude of the voltage applied to the control gate. The non-selected lines (X) are held at ground potential during writing. The Y selection is accomplished by holding the selected source and drain diffusions at 0 volts and the non-selected lines at a positive voltage.

Selective reading is accomplished by using the control gate lines for X selection and the source and drain lines for Y selection. The X lines are at 0 volts for non-selected lines and at a suitable positive voltage for the selected line. The control circuits used to select the X lines are the same circuits for reading and writing; however, a smaller voltage is used in the former case. The selected source diffusions are at 0 volts for the selected lines, and the selected drain lines are at a suitable positive voltage. The non-selected source and drain lines are at 0 volts. Successful operation in an X-Y arra...