Abstract: A complex coupled (gain coupled or loss coupled) distributed feedback (DFB) semiconductor laser, having two sections axially distinct along a cavity length direction, and two excitation means for independent pumping of corresponding sections of the laser in a master and slave type of pumping control, is provided. An extended continuous wavelength tuning range of the laser is obtained by selectively activating a left Bragg mode or a right Bragg mode across the stop band of the laser as a dominant lasing mode by the master and slave type of current injection control into different sections of the laser to alternate gain coupling and loss coupling mechanisms of laser operation, and further tuning a wavelength around the activated Bragg mode. Methods of operating the laser, enhancing a tuning range, and fabricating thereof are provided.

Abstract: A linear and symmetrical gigaohm resistive load structure for an integrated circuit is implemented using a thin film accumulation mode MOSFET configured as a split gate symmetrically off device. Preferably, the resistive load structure comprises two thin film accumulation mode field effect transistors connected in series with a common node and separate gate electrodes. The thin film devices are provided with undoped or lightly doped polysilicon channel regions to provide a desired gigaohm resistance value. By connecting each of the two gate electrodes to the respective source terminals, a two terminal gigaohm resistor structure is produced in which one of the devices is always in the high impedance OFF state regardless of the terminal voltages. The split gate structure allows the integration of the device with minimal metallization interconnect and only two terminals.

Abstract: A low temperature CVD method is provided for depositing high quality stoichiometric, poly-crystalline silicon carbide films and for depositing emitter quality, heavily doped silicon carbide films, suitable for application in silicon hetero-junction bipolar transistors. The process is compatible with bipolar-CMOS device processing and comprises pyrolysis of di-tert-butyl silane in an oxygen free ambient, with n-type doping provided by phosphorus source comprising tert-butyl phosphine. Advantageously oxygen is excluded from the reactant gas mixture and the method includes pre-cleaning the susbtrate with nitrogen trifluoride and passivating the silicon carbide film with fluorine species from nitrogen trifluoride.