The self-heating effect poses a main problem for high-power electronic and optoelectronic devices based on gallium nitride. A non-uniform distribution of the dissipated power and a rise of the average temperature inside the gallium nitride heterostructure field-effect transistor lead to the formation of a hot spot near the conducting channel and result in the degradation of the drain current, output power and device reliability. The purpose of this work is to develop the design of a gallium nitride heterostructure field-effect transistor with an effective heat-removal system and to study using numerical simulation the thermal phenomena specific to this device. The objects of the research are the device structures formed on sapphire, each of whom features both a graphene heat-eliminating element on its top surface and a trench in the passivation layer filled by a high thermal conductivity material. The subject of the research is the electrical and thermal characteristics of these device structures. The simulation results verify the effectiveness of the integration of the heat-removal system into the gallium nitride heterostructure field-effect transistor that can mitigate the self-heating effect and improve the device performance. The advantage of our concept is that the graphene heat-eliminating element is structurally connected with a heat sink and is designed for removing the heat immediately from the maximum temperature area through the trench in which a high thermal conductivity material is deposited. The results can be used by the electronics industry of the Republic of Belarus for developing the hardware components of gallium nitride power electronics.
High Thermal Conductivity of Gallium Nitride (GaN) Crystals Grown by HVPE Process
