AlGaN/GaN HEMT device physics and electrothermal modeling

Gallium nitride (GaN) has emerged as one of the most attractive materials for radio frequency (RF) and power conversion technologies that require high-power and high-frequency devices. This is due to the superior material properties of GaN including the wide bandgap (E g =3.4eV), high saturation velocity (v s =3×107 cm/s), good electron mobility, large critical electric field (E c ~3MV/cm), and reasonable thermal conductivity (κ~150W/m-K at room temperature). The ~10× higher breakdown field than Si makes GaN devices suitable for high voltage operations while the high saturation velocity ensures its applicability for high-frequency operations, as shown in references. Among the various GaN-based devices, AlGaN/GaN high electron mobility transistors (HEMTs) are suitable for high-power applications due to their low on-resistance that stems from the two-dimensional electron gas (2DEG) formed near the AlGaN/GaN heterointerface due to the spontaneous and piezoelectric polarizations of GaN and AlGaN. In this chapter, we will explain detailed procedures to perform electrothermal modeling of AlGaN/GaN HEMTs.