Gate leakage effects and breakdown voltage in metalorganic vapor phase epitaxy AlGaN/GaN heterostructure field-effect transistors

The gate leakage behavior in AlGaN/GaN heterostructure field-effect transistors was studied as a function of applied bias, temperature, and surface periphery. A surface hopping conduction mechanism with an activation energy of 0.21 eV is proposed for the gate-drain leakage for voltages that exceed pinchoff. The reverse breakdown voltage of the device exhibited a negative temperature coefficient of -0.11 VK^-1, suggesting that a breakdown mechanism other than impact ionization, such as thermal runaway, may be responsible.