GaN Power FETs: from Lateral to Vertical

Abstract：
Gallium nitride (GaN) has a bandgap of 3.4 eV, a high breakdown electric field over 3 MV/cm, and a high electron mobility over 1100 cm2/Vs; each of these material properties make the GaN device the most promising technology for the next generation of power switching applications. Due to the high conductivity of the two-dimensional electron gas (2DEG) induced by the difference in the polarization charges of AlGaN and GaN at the AlGaN/GaN heterostructure, GaN power devices have been mostly lateral in topology, as we see in high electron mobility transistor (HEMT). However, for higher power-density and higher total power (>10 kW), devices with a vertical topology are necessary. In this talk, two typical vertical GaN FET structures will be introduced: 1) the current aperture vertical electron transistor (CAVET); and 2) the trench MOSFET. A roadmap to achieve 1.2 kV class switch will be analyzed. Achievements and challenges on vertical GaN FETs will be discussed.