Gallium nitride on silicon in-plane gate field-effect transistors

Giovanni Santoruvo and Elison Matioli of École Polytechnique Fédérale de Lausanne in Switzerland have combined in-plane gate field-effect transistors (IPGFETs) with gallium nitride (GaN) on silicon technology with a view to high-frequency power applications [IEEE Electron Device Letters, published online 9 August 2017]. The IPGFET (Figure 1) uses gate electrodes etched from the same level as the channel to control current flow. There is no need for dielectrics since the gate is insulated from the channel by air. Santoruvo and Matioli comment: “High-frequency devices require a small gate capacitance in addition to a large gm [transconductance], which is an intrinsic advantage of IPGFETs.” Although IPGFETs have been realized in other compound semiconductor materials, Santoruvo and Matioli claim that their work is the first to use III-nitrides to produce high-performance IPGFETs. III-nitride should enable access to high carrier density and high breakdown voltages.