Optically controlled characteristics of III–V Nitride based MM-wave transit-time devices
2009 Applied Electromagnetics Conference (AEMC)
High-frequency characteristics of IMPATT Oscillators based on III-V Indium Phosphide (InP), III-V Wurtzite Gallium Nitride (Wz-GaN) and IV-IV Silicon Carbide (3C, 4H and 6H polytypes) are studied and their performances are compared at a frequency of 0.3THz. A double drift p + p n n + structure is chosen for all the materials and investigation has been carried out to obtain maximum conversion efficiency and device negative resistance by optimizing bias current density through modeling and
... ion technique. A double iterative computer method based on modified drift-diffusion model has been used to study their performance. The simulation studies reveal that these devices are potential sources for generating high power in the Terahertz regime. The avalanche response time for each of the IMPATT diodes are simulated by a newly developed simulation technique and it has been observed that avalanche response time in InP, GaN and SiC IMPATTs are less than the corresponding transit time of the diodes-which is an essential condition to generate THz oscillation in these devices. The conversion efficiency of III-V InP IMPATT diode is found to be 18.4% at 0.3THz with an output power of 2.81W, whereas, III-V Wz-GaN IMPATT is found to generate much higher output power of 6.23W with a conversion efficiency of 15.47% at 0.3THz. On the other side, IMPATTs based on IV-IV SiC generate output power of 11.5W (3C-SiC), 20W (4H-SiC) and 7.5W (6H-SiC) with corresponding conversion efficiencies of 12.5% (3C-SiC), 15% (4H-SiC) and 12% (6H-SiC) at 0.3THz. The extensive simulation results reveal that though IMPATT diode based on SiC gives better performance in terms of higher output power in the Terahertz domain compared to other materials, GaN IMPATT has the advantage of higher efficiency. The design data and the proposed fabrication methodology, presented in this paper, will be helpful to realize InP, SiC and GaN based IMPATT oscillators for Terahertz communication. 98 for hidden weapons, explosives, drugs or other contraband, remote sensing, imaging, spectroscopy, secure wireless communication, biological and medical applications, cancer detection, bio-chip analysis of DNA, proteins or other biological materials, detection of land mines, inspecting defects in semiconductor wafers, detection of chemical and biological warfare agents, monitoring manufacturing processes, determining thickness of a layer of paint, etc. While technological developments remain an ongoing need, commercially products are coming up to address some of the needs of the high profile markets. With the availability of CW and pulse sources, investigators are pursuing potential THz wavelength applications in many fields. To keep pace with such rapid developments, a tremendous urge is observed among scientist worldwide to develop high power Terahertz solid state sources. Among all the solid state sources already available, IMPATT diode have emerged as the most powerful one at microwave and millimeter wave frequency range. Thus covering a wide range of frequency spectrum, this diode find wide applications as solid state transmitters in tracking radars, missile seekers, radiometers and in various civilian, military and space communication systems.