Design and THz characteristics of hexagonal and cubic SiC based photo-irradiated IMPATT oscillators

The millimeter and sub-millimeter wavelength range for a long time has been used in many research applications. This frequency range has been utilized in spectroscopy, radio astronomy, plasma diagnostics, and the study of the earth´s atmosphere. Even millimeter waves are now used in commercial applications as well, particularly in the security sector. An example of a solid-state source of this range is IMPATT diodes. This paper reports on comparative analysis of photosensitivity of 4H-SiC, 6H-SiC, and 3C-SiC based IMPATT diodes at THz regime. Results show that 4H-SiC based IMPATT at THz regime is far better than its other counterparts. Also, this device is found to be more photosensitive than 6H-SiC and 3C-SiC based ones under similar operating conditions.