Terahertz oscillation in GaN HEMT-like BEAN diode with a composite contact

The Well-designed Schottky-ohmic anode contact is demonstrated to effectively suppress the impact ionization concentrated at the anode side in the ultra-short 2-DEG channel of the GaN HEMT-like ballistic electron acceleration (HBEAN) diode which is investigated as a potential terahertz oscillator. An empirical velocity-field characteristics is employed, which is derived from the experimental data and accounts for the presence of ballistic electron acceleration and inter-valley transfer in the GaN channel. Simulations reveal that surface donor-like traps results in the deterioration of the Gunn oscillation and the cut-down effect of the composite contact, the effect of which is greatly related to its energy level. These works are predicted to have positive significance in practice manufacture of THz electron devices.