Abstract: A process for fabricating an integrated group III nitride structure comprising high electron mobility transistors (HEMTs) and Schottky diodes, and the resulting structure, are disclosed. Integration of vertical junction Schottky diodes is enabled, and the parasitic capacitance and resistance as well as the physical size of the diode are minimized. A process for fabricating an integrated group III nitride structure comprising double-heterostructure field effect transistors (DHFETs) and Schottky diodes and the resulting structure are also disclosed.

Abstract: A circuit for generating chaotic signals implemented using heterojunction bipolar transistors (HBTs) and utilized in low probability intercept communications. The HBT chaotic circuit generates truly random analog signals in the GHz range that are non-repeating and deterministic and may not be replicated by preloading a predetermined sequence. A fully differential autonomous chaotic circuit outputs two pairs of chaotic signals to be used in a communication system. As it is impossible to generate identical chaotic signals at the transmitter and receiver sites, the receiver itself sends the chaotic signal to be used for encoding to the transmitter. The receiver includes a chaotic signal generator and digitizes, upconverts, and transmits the generated chaotic signal to the transmitter. The transmitter uses the received chaotic signal to code data to be transmitted. The receiver decodes the transmitted data that is encoded by the chaotic signal to retrieve the transmitted data.

Abstract: A process for fabricating an integrated group III nitride structure comprising high electron mobility transistors (HEMTs) and Schottky diodes, and the resulting structure, are disclosed. Integration of vertical junction Schottky diodes is enabled, and the parasitic capacitance and resistance as well as the physical size of the diode are minimized. A process for fabricating an integrated group III nitride structure comprising double-heterostructure field effect transistors (DHFETs) and Schottky diodes and the resulting structure are also disclosed.

Abstract: A post-distortion method for cascading amplifier stages in a two-stage microwave power amplifier and a dynamic biasing method using back-end processing for correcting nonlinearity in the power amplifier output. A first or driver stage biased in a near-A region with low distortion is cascaded with a second or power stage biased in a near-C region with high efficiency. The amplitude and phase responses of the two stages compensate another to yield a more linear overall gain for the overall power amplifier. The dynamic biasing scheme modulates the source to drain voltages of the transistors used in the amplifier stages based on the harmonics in amplifier output in order to minimize the harmonics and correct non-linearity in the output.

Abstract: A circuit for generating chaotic signals implemented using heterojunction bipolar transistors (HBTs) and utilized in low probability intercept communications. The HBT chaotic circuit generates truly random analog signals in the GHz range that are non-repeating and deterministic and may not be replicated by preloading a predetermined sequence. A fully differential autonomous chaotic circuit outputs two pairs of chaotic signals to be used in a communication system. As it is impossible to generate identical chaotic signals at the transmitter and receiver sites, the receiver itself sends the chaotic signal to be used for encoding to the transmitter. The receiver includes a chaotic signal generator and digitizes, upconverts, and transmits the generated chaotic signal to the transmitter. The transmitter uses the received chaotic signal to code data to be transmitted. The receiver decodes the transmitted data that is encoded by the chaotic signal to retrieve the transmitted data.

Abstract: A voltage comparator including a quantum tunneling coupled transistor and a method for tuning the voltage comparator. The comparator includes a quantum tunneling coupled transistor coupled to a resistor and is capable of operating above 10 Giga-samples-per-second or a clock rate of 10 GHz. The comparator has a low power consumption of about 1 mW excluding the power required for clock generation and independent from the sampling rate. The threshold or reference voltage of the comparator is controllable by adjusting the pulse height of the clock signal. The comparator has relatively low hysteresis estimated at about 1 mV.

Abstract: A post-distortion method for cascading amplifier stages in a two-stage microwave power amplifier and a dynamic biasing method using back-end processing for correcting nonlinearity in the power amplifier output. A first or driver stage biased in a near-A region with low distortion is cascaded with a second or power stage biased in a near-C region with high efficiency. The amplitude and phase responses of the two stages compensate another to yield a more linear overall gain for the overall power amplifier. The dynamic biasing scheme modulates the source to drain voltages of the transistors used in the amplifier stages based on the harmonics in amplifier output in order to minimize the harmonics and correct non-linearity in the output.

Abstract: A comparator uses two resonant tunneling diodes (RTDs) in series with resistors of the latch element of the comparator. By inserting two RTD diodes in series with resistors, the negative resistance of the first and the second RTD diodes reduces the effective RC time constants of the resistors and latch, leading to a faster regeneration during a latching mode of the comparator than achieved with alternative designs.

Abstract: A comparator uses two resonant tunneling diodes (RTDs) in series with resistors of the latch element of the comparator. By inserting two RTD diodes in series with resistors, the negative resistance of the first and the second RTD diodes reduces the effective RC time constants of the resistors and latch, leading to a faster regeneration during a latching mode of the comparator than achieved with alternative designs.

Abstract: A heterostructure complementary transistor switch (HCTS) is fabricated using epitaxial layers on a substrate to form the desired P-N-P-N (or N-P-N-P) complementary structure in III-V compound semiconductor materials. Two HCTS are formed on a single substrate to form a memory cell. A collector and a base on one of the HCTs are connected to a base and a collector, respectively, on the other HCTS to form the memory cell.