70 GHz GaAs Tunnett Diode

The fabrication and investigation of GaAs-Tunnett diodes for V-band frequencies are described. The initial material for the device fabrication is obtained by GaAs MBE technology. The measured I(U)-characteristics of the Tunnett diodes fit very well with the used theoretical model. A comparison of the low frequency noise behaviour of Tunnett and Impatt diodes shows significantly lower values for the Tunnett diodes. Experimental results of rf-power and minimum detectable signal in self-oscillating mixer application for frequencies in the upper V-band and W-band are presented. The Tunnett diodes exhibit up to 25 mW cw output power with a maximum efficiency of 2.8 % and the minimum detectable signal in self-oscillating mixers is measured to be as low as -132 dBm. Preliminary phase noise measurements at 94 GHz show a noise measure of about 18 dB.