Abstract: A resilient majority driver accepts triple-redundant input signals and provides a robust output signal unaffected by static errors on one of the input signals or by single-event transients caused by radiation within the driver. Data, clock, and asynchronous input signals to DICE (Dual Interlocked storage CEll) flip-flops in a register are driven by resilient majority drivers to construct an input-protected DICE register. Static errors are corrected using triple-redundant inputs and majority voting, while single-event strikes are largely corrected by the DICE architecture within each flip-flop and by the resilient majority drivers. Remaining errors in the input-protected DICE registers, such as those caused by single-event transients occurring during clock transitions, are corrected by error-correction encoders and decoders, whose output transients are suppressed by glitch filters.

Abstract: Expansion compensating structures are formed in redistribution layers of a wafer-level chip-scale integrated circuit package (WLCSP) or other IC package having a low-expansion substrate. The structures include micromechanical actuators designed and oriented to move solder bumps attached to them in the same direction and distance as a function of temperature as do pads to which they may be connected on a higher-expansion substrate such as a printed circuit board. Expansion compensated IC packages incorporating these expansion compensating structures are provided, as well as expansion compensated assemblies containing one or more of these IC packages. Methods of fabricating expansion compensated IC packages requiring minimal changes to existing commercial WLCSP fabrication processes are also provided. These devices and methods result in assemblies having improved board-level reliability during thermal cycling, and allow the use of larger IC die sizes in WLCSP technology.

Abstract: Systems and methods for shutting down a functional circuit in response to a predetermined total ionizing dose of radiation employ at least two redundant sensing circuits operated in integrate and measure phases by one or more sequencer-type hardware or software controllers. NMOS TID sensors having leakage currents increasing monotonically with dose may be biased during integrate phases, with bias voltages or duty cycles adjusted to achieve a calibrated responsivity. TID measurements are compared to a corresponding reference, latched to generate overexpose signals, and tested for agreement. Disagreement triggers remeasurement to prevent erroneous shutdown until a minimum number of overexpose signals agree that TID exceeds the predetermined threshold. A disable circuit accepts the redundant overexpose signals and generates a signal to disable a functional circuit.

Abstract: Devices with increased susceptibility to ionizing radiation feature multiple parasitic transistors having leakage currents that increase with total ionizing dose (TID) due to negative threshold shifts from radiation-induced charge buildup in the field oxide. Leakage currents of parasitic edge transistors associated with active region sidewalls under a gate are enhanced using branching gate patterns that increase the number of these sidewalls. Other variations combine parasitic edge transistors with parasitic field transistors formed under the field oxide between active regions, or between n-wells and active regions. Arrays of such devices connected in parallel further multiply leakage currents, while novel compact designs increase the density and hence the sensitivity to TID for a given circuit area.

Abstract: Expansion compensating structures are formed in redistribution layers of a wafer-level chip-scale integrated circuit package (WLCSP) or other IC package having a low-expansion substrate. The structures include micromechanical actuators designed and oriented to move solder bumps attached to them in the same direction and distance as a function of temperature as do pads to which they may be connected on a higher-expansion substrate such as a printed circuit board. Expansion compensated IC packages incorporating these expansion compensating structures are provided, as well as expansion compensated assemblies containing one or more of these IC packages. Methods of fabricating expansion compensated IC packages requiring minimal changes to existing commercial WLCSP fabrication processes are also provided. These devices and methods will result in assemblies having improved board-level reliability during thermal cycling, and allow the use of larger IC die sizes in WLCSP technology.

Abstract: Devices with increased susceptibility to ionizing radiation feature multiple parasitic transistors having leakage currents that increase with total ionizing dose (TID) due to negative threshold shifts from radiation-induced charge buildup in the field oxide. Leakage currents of parasitic edge transistors associated with active region sidewalls under a gate are enhanced using branching gate patterns that increase the number of these sidewalls. Other variations combine parasitic edge transistors with parasitic field transistors formed under the field oxide between active regions, or between n-wells and active regions. Arrays of such devices connected in parallel further multiply leakage currents, while novel compact designs increase the density and hence the sensitivity to TID for a given circuit area.

Abstract: Compact radiation-hardened NMOS transistors permitting close spacing for high circuit density can be fabricated using modern commercial foundry processes incorporating lightly-doped drain (LDD) and silicidation techniques. Radiation-induced leakage currents in parasitic field oxide transistors are reduced by spacing diffusions away from field oxide edges under the gate, forming gap regions from which n-type dopants and silicide formation are excluded using blocking patterns in the layout. P-type implants along these field oxide edges further increase radiation tolerance. Dimensions can be tailored to permit tradeoffs between radiation tolerance, breakdown voltage, and circuit density. Compact layouts for series-connected NMOS transistors are provided and applied to high-density rad-hard circuits. Methods for fabricating devices having these features are also provided, requiring minimal adaptation of standard processes.

Abstract: CMOS output stages, electrostatic discharge (ESD) protection circuits and input bus-keeper functions are provided that block dc and ac leakage paths within inactive powered-down integrated circuits used in redundant high-reliability system configurations employing cold-sparing to provide backup circuitry. These circuits and methods avoid both undesirable power consumption in a cold-spared backup unit and loading of connected active units when powered down, without compromising performance or functionality of the backup unit when in its active powered state. Inputs and outputs using an analog majority voting principle to implement in-circuit redundancy for on-chip fault tolerance are also provided, incorporating the low-leakage principles of the invention for low power dissipation when powered down. Such on-chip redundancy can harden an IC against various faults, such as single-event effects in high-radiation environments, while maintaining the other advantages in a cold-sparing system.

Abstract: An integrated circuit for use in high-reliability electronic systems contains one or more digital majority voters with corresponding disagreement detectors connected to the same input signals producing a majority value output and an error signal that is active when not all input signals agree. Internal error signals from multiple majority voter/disagreement detectors as well as external error inputs may be combined using disjunctive error logic to produce an “error detected” output indication. Cold-sparing and hot-plugging are supported by providing cold-sparable electrostatic discharge protection circuits and power-on reset circuitry controlling cold-sparable output stages. Internal modular redundancy provides immunity to single-event transients as well as enhanced reliability.

Abstract: Systems and methods for fault-tolerant threshold circuits used in converting an analog input to a single-bit digital output employ N-modular redundancy of either inverting or non-inverting threshold circuits whose inputs are connected to a single input, and apply majority voting of their outputs to provide correction of transient or permanent faults in up to floor[(N?1)/2] of the individual threshold circuits. Using summation to perform analog majority voting averages the N threshold circuit outputs and provides resilience to single-event transients, but may exhibit an output characteristic having intermediate voltage levels. A digital majority voter having N inputs connected to the outputs of N threshold circuits restores well-defined logic levels and clean hysteresis for Schmitt trigger threshold circuits. A single point of failure at the digital majority voter may be eliminated using an analog majority voter to sum the outputs of three or more redundant digital majority voters.

Abstract: Compact radiation-hardened NMOS transistors permitting close spacing for high circuit density can be fabricated using modern commercial foundry processes incorporating lightly-doped drain (LDD) and silicidation techniques. Radiation-induced leakage currents in parasitic field oxide transistors are reduced by spacing diffusions away from field oxide edges under the gate, forming gap regions from which n-type dopants and silicide formation are excluded using blocking patterns in the layout. P-type implants along these field oxide edges further increase radiation tolerance. Dimensions can be tailored to permit tradeoffs between radiation tolerance, breakdown voltage, and circuit density. Compact layouts for series-connected NMOS transistors are provided and applied to high-density rad-hard circuits. Methods for fabricating devices having these features are also provided, requiring minimal adaptation of standard processes.

Abstract: CMOS output stages, electrostatic discharge (ESD) protection circuits and input bus-keeper functions are provided that block dc and ac leakage paths within inactive powered-down integrated circuits used in redundant high-reliability system configurations employing cold-sparing to provide backup circuitry. These circuits and methods avoid both undesirable power consumption in a cold-spared backup unit and loading of connected active units when powered down, without compromising performance or functionality of the backup unit when in its active powered state. Inputs and outputs using an analog majority voting principle to implement in-circuit redundancy for on-chip fault tolerance are also provided, incorporating the low-leakage principles of the invention for low power dissipation when powered down. Such on-chip redundancy can harden an IC against various faults, such as single-event effects in high-radiation environments, while maintaining the other advantages in a cold-sparing system.

Abstract: CMOS output stages, electrostatic discharge (ESD) protection circuits and input bus-keeper functions are provided that block dc and ac leakage paths within inactive powered-down integrated circuits used in redundant high-reliability system configurations employing cold-sparing to provide backup circuitry. These circuits and methods avoid both undesirable power consumption in a cold-spared backup unit and loading of connected active units when powered down, without compromising performance or functionality of the backup unit when in its active powered state. Inputs and outputs using an analog majority voting principle to implement in-circuit redundancy for on-chip fault tolerance are also provided, incorporating the low-leakage principles of the invention for low power dissipation when powered down. Such on-chip redundancy can harden an IC against various faults, such as single-event effects in high-radiation environments, while maintaining the other advantages in a cold-sparing system.