Abstract: In an EEPROM memory cell of the kind which relies on tunneling action through a thin oxide layer to store charge on a floating gate, the floating gate and the channel regions of the memory cell are provided with additional doping of the same kind as in the substrate in order to raise the virgin state threshold voltage of the memory cell to a high positive value, such as 4 volts. Additionally, the overlap area between the control gate and the floating gate is reduced to the extent that the capacitance between the floating gate and the control gate is substantially equal to the capacitance between the floating gate and the substrate during programming, but the effective capacitance between the floating gate and the substrate is greatly reduced during erase mode. As a result, little or no tunneling occurs during programming and the threshold voltage level is the same as the virgin threshold value of the memory cell.

Abstract: In fabricating a PROM cell, an electrical isolation mechanism (44 and 32) is formed in a semiconductive body to separate islands of an upper zone (36) of first type conductivity (N) in the body. A semiconductor is introduced into one of the islands to produce a region (48) of opposite type conductivity (P) that forms a PN junction with adjacent semiconductive material of the island. Ions are implanted to convert a surface layer (60) of the region into a highly resistive amorphous form which is irreversibly switchable to a low resistance state. A path of first type conductivity extending from the PN junction through another of the islands to its upper surface is created in the body to complete the basic cell.

Abstract: An ISL structure is fabricated by a process in which impurities are introduced into a semiconductor substrate (10) of first type conductivity (P) to form major and minor portions (18 and 18a) of a first region of opposite second type conductivity (N). The minor portion has a lower net impurity concentration than the major portion and extends to a considerably lesser depth. An impurity is introduced into the major and minor portions to form a second region (24) of first type conductivity. An impurity is introduced into the second region to form a third region (30) of second type conductivity spaced laterally apart from the minor portion. Metallization is then performed to create at least one Schottky rectifying contact (32) with the major portion and ohmic contacts (38, 36, and 34) with the substrate and second and third regions.

Abstract: A film of titanitum-tungsten nitride is used to provide the dual function of a fuse link between a semiconductive device and an interconnect line in a memory array and of a barrier metal between another metal and a semiconductor region.

Abstract: A MOS power-on reset circuit includes Schmitt trigger circuit and an inverter. The Schmitt trigger circuit comprises first, second, and third depletion transistors serially connected between reference potential and supply voltage. The first and second depletion transistors are connected at a first junction point, and the second and third depletion transistors are connected at a second junction point. The gates of the first and second depletion transistors are commonly connected for receiving an input substrate bias voltage. An enhancement transistor is connected between the first junction point and supply voltage. The gates of the enhancement transistor and the third depletion transistor are commonly connected to the second junction point, which is the output of the Schmitt trigger circuit and which is coupled to the inverter from which the output voltage is taken.

Abstract: A bistable switching circuit contains a pair of like-polarity input transistor circuits (Q1 and Q2) arranged in a differential configuration to receive a corresponding pair of input signals. A pair of like-polarity cross-coupled transistor load circuits (Q3 and Q4) complementary to the input transistor circuits are coupled to them. A pair of resistive elements (R1 and R2) are coupled between a voltage supply (V.sub.CC) and the load transistor circuits. An output transistor (Q5) complementary to the input transistor circuit has its control electrode and one of its flow electrodes coupled across one (Q4) of the load transistor circuits. When the input signals assume values capable of causing the output transistor to turn on, no current flows in the output transistor until regeneration occurs in the load transistor circuits -- i.e., until they switch states.

Abstract: In a memory cell array of the kind including a memory cell capacitor and a memory cell transistor connected in series between a field plate line and a bit line, both the field plate line and bit line are precharged to the same potential level. The field plate line is connected to one input of a sense amplifier and the bit line is connected to the other input. The charge and discharge of the memory cell capacitor causes equal and opposite voltage changes on the field plate line and bit line. With respect to prior art the cell signal is increased by the amount of signal on the field plate line and when sensed against a reference signal which is about one-half the amount of the cell signal, the sensed signal is about twice that obtainable in the prior art.

Abstract: The edge profile of a silicon layer is shaped to have a gradual incline considerably less than 90.degree. by continuously reducing the amount of oxygen mixed with carbon tetrachloride in a reactive ion etching environment. The etching mode varies from complete isotropic etching when the amount of oxygen is maximum, to complete anisotropic etching when the oxygen content is zero.

Abstract: An arbiter circuit includes a latch made of two crosscoupled NAND gates, one of which is a Schmitt NAND gate, a difference detector, and two output NOR gates. The output of the latch is coupled to the difference detector and to one input of the NOR gates. The NOR gates receive another input from the difference detector. The difference detector is responsive to a voltage difference that exceeds one V.sub.BE, thereby blocking signals that originate in the latch during oscillating or metastable states of the latch, which may include rut pulses.

Abstract: A multiplexed data monitoring system for use in monitoring the status of control valves or the like in subsea petroleum well control systems, utilizes an encoder circuit located externally of the control module and composed of passive electrical components, such as inductors and capacitors, to encode switch contact closure or status information into discrete frequency data. The external encoder circuit is coupled by a pair of wires to the control module.The decoder circuitry within the subsea control module applies an alternating current signal of varying frequency to the encoder circuit and by monitoring the phase of the alternating current, the decoder circuitry can recover the data impressed by the switch contacts at the status points, which are also located externally of the control module.