Submillimeter Wave Oscillation from GaAs Tunnett Diode

The Tunnel injection transit time negative resistance (Tunnett) diode has been thought to be useful active device in the frequency range from 100 to 1000 GHz and will be positioned as a semiconductor device between the GaAs static induction transistor (SIT) and Raman- and Brillouin-lasers. Tunnett diode shows very low noise properties and operates with low applied voltage less than 10 V. GaAs Tunnett diodes with p+-n, p+-n-n+ and p+-n+-n-n+ structures have been fabricated by a new LPE (TDM under CVP) method. The submillimeter wave fundamental oscillation up to 338 GHz (¿=0.89 mm) has been obtained from the pulse driven GaAs p+-n-n+ diode at biasing power of 8.6 W. The oscillation frequency of the Schottky barrier diode (Pt-n-n+) fabricated has been 153 GHz and shows larger temperature dependence and lower efficiency than those of the GaAs p-n junction Tunnett diode. The lowest d.c. power for the oscillation has not been enough to achieve the CW operation and is expected to be improved by the introduction of the new design and also the p+-n+-n-n+ structure and the Gunnett diode will be discussed.