Prospects of β-SiC Based IMPATT Oscillator for Application in THz Communication and Growth of β-SiC p-n Junction on Ge Modified Si <100> Substrate to Realize THz IMPATTs

The prospects of p+ n n+ cubic Silicon Carbide (3C-SiC/ß-SiC) based IMPATT diode as a potential solid-state Terahertz source is studied for the first time through a modified generalized simulation scheme. The simulation predicts that the device is capable of generating a RF power output of 63.0 W at 0.33 THz with an efficiency of 13%. The effects of parasitic series resistance on the device performance and exploitable RF power level are further simulated. The studies clearly establish the potential of 3C-SiC as a base semiconductor material for high-power THz IMPATT device. Based on the simulation results an attempt has been made to fabricate β- SiC based IMPATT devices in THz region. Single crystalline, epitaxial 3C-SiC films are deposited on silicon (Si) <100> substrates by Rapid Thermal Chemical Vapour Deposition (RTPCVD) at a temperature as low as 800 0C using a single precursor methylsilane, which contains Si and C atoms in the same molecule. No initial surface carbonization step is required in this method. A p-n junction with n-type doping conc. of 4 x 10^24 m-3 (which is similar to the simulated design data) has been grown successfully and the characterization of the grown 3C-SiC film is reported in this paper. It is found that the inclusion of Ge improves the crystal quality and reduces the surface roughness.