Normally-off AlGaN/GaN-on-Si MOSHFETs with TaN floating gates and ALD SiO2 tunnel dielectrics

In this work, we have demonstrated a normally-off AlGaN/GaN metal-oxide semiconductor heterojunction field effect transistor (MOSHFET) wherein the enhancement mode operation is enabled by charge storage within a metal floating gate embedded in a dielectric stack and negative charges in the tunnel oxide. By combining ALD SiO₂ and TaN floating gate (FG), up to 6V of V_T shift after pulse programming (corresponding ~1.2×10¹³ charges/cm² stored within the FG) is obtained which results in a normally-off device with low gate leakage and good transconductance.