Fabrication and analysis of GaAs Schottky barrier diodes fabricated on thin membranes for terahertz applications

The GaAs Schottky diode is predominantly used as the critical mixer element in heterodyne receivers in the frequency range from 300 GHz to several THz1]. At operating frequencies above one THz the skin effect adds significant parasitic resistance to the diode which degrades the receiver sensitivity. A novel diode structure called the Schottky barrier membrane diode is proposed to decrease the skin effect resistance by reducing the current path between the Schottky and ohmic contacts. This is accomplished by fabricating the diode on a very thin membrane of GaAs (about 1 μm thickness). A theoretical analysis has shown that this will reduce the substrate resistance by 60% at 3 THz. This reduction in resistance corresponds to a better frequency response which will improve the device's performance as a mixer element.