Abstract: A method for forming electrical interconnections in an integrated circuit which involves forming an insulating layer on the silicon chip on the lower of two conductive layers to be interconnected, opening a window in the insulating layer, filling the window with a metallic plug by a lift-off technique, and then forming an interconnection pattern extending over the layer and contacting the plug.

Abstract: A logic gate is formed as a full 3-EFL circuit including a full two-level ECL current switch tree and an EFL stage made up of input and output multiemitter transistors. By appropriate connections, the logic gate may be used for a variety of circuits including a 4:1 multiplexer and a comparator of two three-digit binary numbers. The logic gate advantageously is formed in a silicon chip which includes an array of cells each consisting essentially of nine single-emitter transistors, two four-emitter transistors and a number, advantageously nine, of resistors.

Abstract: A dry etching process for aluminum uses a silicon tetrachloride gas ambient to which is applied radio frequency power for ionizing the gas. By appropriate control of the gas pressure and power density, anisotropic etching is achieved. This gas system also is useful for etching dual layers of aluminum and doped polycrystalline silicon.

Abstract: An MOS parallel carry synchronous binary counter/clock rate divider circuit has a chain of simultaneously clocked T flip-flop interconnected by an improved enable logic circuit having a plurality of identical carry stages each associated with a different flip-flop except the first and last flip-flop of the chain. Each carry stage has an input terminal connected to the inverted enable input of its associated flip-flop, an output terminal connected to the inverted enable input of the next flip-flop in the chain, a transmission gate transistor having a conduction channel connected in series between the input and output terminals and a gate connected to the normal output of the associated flip-flop, and a depletion mode load transistor having a conduction channel connected between a VDD power supply terminal and the output terminal and a gate connected to the output terminal.

Abstract: A chain-type ripple-carry generating circuit having a plurality of cascaded stages is provided with a regeneration network in each stage for restoring the logic level of a carry signal propagating through the stage. In one embodiment of the invention the regeneration network is designed to restore a carry-not bit and comprises an MOS transistor having its conduction channel coupled between the input of the stage and a ground terminal, the gate of the transistor being driven by a two-input NOR gate, one input of the NOR gate being connected to receive a precharge clock signal and the other input being connected to the input of the stage. When the precharge clock signal is at a logic "0" level and the input of the stage receives a carry-not bit at a logic "0" level, the NOR gate drives the MOS transistor into conduction causing the input of the stage to be pulled to substantially ground potential.

Abstract: A dynamic random access memory in which individual cells, including an access transistor and a storage capacitor, are formed in mesas formed on a silicon chip. The access transistor of the cell is formed on the top surface of the mesa and one plate of the storage capacitor of the cell is formed by the sidewall of the mesa and the other plate by doped polycrystalline silicon which fills the grooves surrounding the mesas isolated therefrom by a silicon dioxide layer. By this geometry, large storage surfaces, and so large capacitances, can be obtained for the capacitor without using surface area of the chip. In other embodiments, the mesas may include other forms of circuit elements.

Abstract: An EFL J-K flip-flop circuit is provided in which feedback of only the true output Q of the slave latch to the input of the master section is required. The circuit in one embodiment includes a slave D-type latch comprising an EFL latch circuit combined with a one level current steering network, a master section comprising an EFL latch circuit combined with a two level current steering network, and an ECL inverter for complementing the K input signal to provide a K signal for the master section. All input combinational logic in the master section, including the complementing of the Q feedback signal, takes place in one emitter coupled transistor pair in the second level of the current steering network and at two input emitters of the master section EFL latch circuit. In an alternative embodiment, the ECL inverter is replaced by a third level current switch in the master section.

Abstract: A clocked IGFET serial decoder circuit has a precharge transistor with its conduction channel connected between a V.sub.DD supply and an output terminal, a string of transistors with their conduction channels connected in series between the output terminal and a switch ground node and a ground switch transistor with its conduction channel connected between the switch ground node and a V.sub.SS supply. The gates of the transistors of the string receive input signals from clocked input buffers which bias the gates at V.sub.DD during the precharge interval when the precharge transistor is ON and the ground switch transistor is OFF. This allows the parasitic capacitances at the junctures of the transistors in the string to become substantially charged during the precharge interval and thus prevent rapid charge sharing at the output terminal when the circuit is enabled.

Abstract: A clocked IGFET logic circuit comprises a precharge transistor having its channel connected between a V.sub.DD supply terminal and an output terminal, a functional network connected between the output terminal and a switch ground node, the network containing a plurality of transistors each having its gates connected to receive a respective one of a plurality of input signals and its channel connected together with those of the other transistors of the functional network in a configuration which provides the circuit with a predetermined logical function, and a ground switch transistor having its channel connected between the switch ground node and a V.sub.SS supply terminal. The gate of the ground switch transistor receives a clock signal which turns that transistor OFF during a precharge phase of the clock signal and ON during an active phase of the clock signal.

Abstract: A logic structure for an LSI digital circuit includes data compression circuitry for deriving a signature word from the data on a multiplicity of internal nodes which are not directly accessible from the terminals of the circuit. The signature word provides error information concerning the data on the internal nodes which are not otherwise available for testing purposes. The addition of data compression circuitry facilitates the testing of LSI digital circuits and can be complemented with minimal overhead chip area.

Abstract: A CMOS integrated circuit structure having an improved guardband configuration for the prevention of parasitic SCR latchup. Included with each guardband is a pair of field reducing surface regions of the opposite conductivity type to that of the guardband and situated one on each side of the guardband adjacent thereto. The field reducing regions which are electrically connected to each other serve to reduce any electric fields in the bulk region underlying the guardband thereby significantly improving the effectiveness of the guardband for collecting minority carriers in the bulk region to provide greater protection from latchup.

Abstract: A rapid and systematic method for performing chip layout of a random-logic IGFET circuit includes steps for arranging the device features and interconnection features corresponding to the circuit in respective positions in an array of intersecting rows and columns. The method provides layouts of device and interconnection features having a high packing density and a high degree of order and regularity to facilitate checking for layout errors.

Abstract: A CMOS integrated circuit structure which is not susceptible to latchup utilizes insulated-gate field-effect transistors having Schottky barrier source and drains (SB-IGFET). In the preferred embodiment, the n-channel device of an adjacent complementary pair of transistors in a CMOS circuit is provided with diffused source and drain while the p-channel device of the pair is provided with PtSi-Si Schottky barrier contact source and drain. Such a structure completely eliminates the parasitic pnpn structure which causes the latchup problem in conventional CMOS structures.

Abstract: A Central Processing Unit (CPU) includes a hardware op-code extending register (OER) for storing a code for programmable selection of optional CPU features which modify processor operations defined by the op-code in each instruction. A control section in the CPU decodes both the op-code of a current instruction and the code in the OER, effectively combining the two to form an extended op-code capable of defining a larger set of processor operations than the op-code carried in each instruction. The code in the OER is changed only when the CPU executes an instruction for transferring a new code into OER. Thus the code in OER can remain stationary over many instruction cycles.

Abstract: An improved IGFET bootstrap driver circuit capable of driving a load impedance to substantially full VDD power supply voltage and holding the load at that voltage for an indefinite period of time. The circuit includes a load transistor, a feedback capacitor connected between the source and gate electrodes of the load transistor, a fix valued resistor connected between the gate electrode of the load transistor and an on-chip bias voltage generating circuit for providing a bias voltage greater than VDD+VT. The resistor and the bias voltage generating circuit provide sufficient current to replenish the charge lost from the feedback capacitor through junction leakage currents in the driver circuit. The resistor is of a sufficiently high value such that the current drain from the generating circuit is insignificantly small in comparison to the current drain from the VDD power supply. The improved circuit also permits the load transistor to be switched "on" or "off" by an externally applied signal.

Abstract: A process for making dielectrically isolated silicon integrated circuits which use silicon oxide filled trenches to provide isolation is described. To minimize damage to the silicon, the trenches are filled by sequentially annealed oxidation process which involves alternately growing some oxide and then annealing to relieve stresses before growing more oxide.

Abstract: An IGFET push-pull driver circuit includes an output stage having pull-up and pull-down IGFETs for driving an output node. An inverter stage drives the gate of the pull-up IGFET. A current sensing IGFET biased to represent a resistance is coupled between the pull-up IGFET and the output node to provide a voltage drop which is proportional to the current flowing through the pull-up IGFET. A regulating IGFET with its channel coupled between the gate of the pull-up IGFET and the output node and with its gate coupled to the juncture of the pull-up IGFET and the current sensing IGFET, responds to the voltage drop across the current sensing IGFET to provide feedback control of the conductance of the pull-up IGFET. The maximum output current of the driver is limited to a value which remains substantially constant over a wide range of processing parameters, operating temperature and load impedance.

Abstract: A Central Processing Unit provides programmable variation of the operand width for processor operations. The operands are formed with one or more N-bit segments. The CPU includes an arithmetic logic unit (ALU) which is adapted to operate serially on one N-bit segment of the operand at a time beginning with the least significant segment and repeating the operation on the remaining segments according to their order of significance. The number of repetitions of an ALU operation is controlled by a code stored in an op-code extension register (OER). The code in the OER can be changed by means of an instruction for transferring a new code to OER.

Abstract: A Central Processing Unit (CPU) provides programmable autoloading of memory pointer registers. The CPU includes an op-code extension register (OER) to store a code specifying the autoloading status of each memory pointer register. Whether or not a particular memory pointer register is loaded at the end of an instruction cycle with an operand address carried by the current instruction depends on the binary state of a particular bit position in the OER corresponding to the particular memory pointer register. The contents of the OER can be changed by means of an instruction for transferring a new code to OER. A CPU architecture having an OER permits software specification of autoloading without significantly increasing the number of op-codes required to define the instruction set. Fewer op-codes generally permit shorter instructions.

Abstract: A memory in which each cell comprises an MOS transistor merged with a storage capacitor and in which the cells are arranged to permit adjacent pairs of transistors in a common column to share a common source and the transistors in a common row to share a common gate electrode conductor. The memory uses a first polycrystalline silicon layer which is patterned to provide interconnected storage electrodes and a second polycrystalline silicon layer which is patterned to provide a plurality of stripes to serve as the bit sense lines and a plurality of gate electrodes.