Abstract: An electrically programmable memory cell of a type having a source, a drain, a floating gate and a control gate formed over a face of a semiconductor substrate in which a ring region of material doped similarly to the substrate encloses the source, drain and gates and extends to a surface of the substrate around its length. Drain and source coupling regions of material doped oppositely to the substrate contact the drain and source, respectively, within the ring and extend under the ring to the substrate surface outside of the ring defining drain and source contact regions, respectively. A contact outside the ring to the control gate is provided by a gate coupling region also extending under the ring to a substrate surface on either side thereof. An interconnect couples the floating gate to the gate coupling region. A non-light transmitting, electrically conducting shield extends over the cell contacting the ring region around its periphery at the substrate surface.

Abstract: A discharge circuit for discharging bit lines of an array of semiconductor memory cells in which the array of bit lines are biased from a single bias line. The discharge circuit includes a discharge switch coupled to the bias line for discharging the bit lines and the bias line and a control circuit coupled to the discharge switch operative to turn on the discharge switch in response to the voltage on the bias line rising above a first predetermined level and then to turn off the discharge switch in response to the voltage on the bias line falling below a second predetermined level.

Abstract: An array of programmable memory cells having spaced apart bit lines, spaced conducting word lines crossing over the bit lines and electrically conductive lead lines crossing over the word line which includes electrically conductive contacts between lead lines and corresponding bit lines. Each contact is located at an opposite side of a selected number of word lines to contacts between adjacent lead lines and associated bit lines so that when viewed in plan the contacts are staggered from one lead line to the next.

Abstract: A method of making an array of programmable read only semiconductor memory cells which includes forming an extra row of the memory cells and a corresponding extra row gate coupled thereto. Extra row gate enabling means is coupled to the extra row gate for enabling the extra row gate in response to a control signal KILLT applied thereto. A disabling means is coupled to a first selected row gate other than the extra row gate in order to disable the selected row gate in response to a control signal KILLT applied thereto. A disabling means is coupled to a first selected row gate other than the extra row gate in order to disable the selected row gate in response to the control signal KILLT being applied thereto.An NAND gate may be formed with the extra row gate to allow a second set of signals corresponding to a second selected row of memory cells to enable the second selected row gate. A disabling means is coupled to the second selected row gate other than the extra row gate.

Abstract: An electrically programmable semiconductor memory device of a type having an array of programmable semiconductor floating gate transistors sets of which are coupled between associated respective source and drain lines, an array programming control transistor and a ground select transistor coupled to each of the drain and source lines. Each selected floating gate transistor in a programming mode is in series with control and ground select transistors between a high voltage Vpp and ground potential. A resistive element in series with a first conducting circuit element establishes a reference current which generates a voltage V.sub.1 at the junction of the resistive element and the circuit element. In a second current leg a second conducting circuit element, a module floating gate transistor biased into a conducting state and a module control transistor are all connected between Vpp and ground such that a voltage V.sub.

Abstract: An array of transistor memory cells of a type in which each cell has a transistor, a ground select switch and a sense amplifier coupling switch. A bias voltage line on which there is established a voltage V.sub.BIAS is coupled to each bit line by a bit line transistor whose gate during a read mode is at least about a voltage V.sub.T above V.sub.BIAS. Similarly, the source of each transistor is coupled to the bias voltage line by a source line transistor whose gate is more than about a voltage V.sub.T about V.sub.BIAS. The foregoing arrangement ensures that for every non-selected transistor that transistor's source voltage will be equal to its drain voltage so that all non-selected transistors will be substantially non-conducting.