An Heterojunction Schottky Barrier Diode with RTD Emitter

The possible application of Schottky diodes as detector elements in receivers and image sensing systems operating in the THz frequency range has been demonstrated in the literature. In addition to metal-semiconductor (M-S) Schottky diodes, the use of heterojunction Schottky barrier diodes for detection and mixing applications has also been explored. Such diodes require lower d.c. bias voltages, which is important for certain types of detector and mixer designs which strive to achieve higher signal-to-noise ratios. A new detector design is proposed which utilizes a heterojunction Schottky barrier and a double barrier structure jointly for high sensitivity detection. The diode is designed so that the resonant energy level of the double barrier structure is lower than the Schottky barrier at low bias and becomes higher than the barrier as bias increases. In this regime, the therm° distribution of emitted electrons is altered by the presence of double barrier structure, leading to a sharp knee point and a significant improvement in sensitivity. As compared with a "plain" heterojunction Schottky diode. high frequency response will be affected by the tunneling time through the RTD in addition to the capacitance from junction itself. Such high frequency influences are discussed. Fifth International Symposium on Space Terahertz Technology Page 743