Enhancement mode GaAs metal-oxide-semiconductor field-effect-transistor integrated with thin AlN surface passivation layer and silicon/phosphorus coimplanted source/drain

By using thin AlN film as a passivation layer between the GaAs and HfO2, GaAs metal-oxide-semiconductor (MOS) devices exhibited well-behaved accumulation and inversion capacitance-voltage characteristics with low leakage current of 6×10−5A∕cm2 at Vg=1V and interface state density of ∼4.9×1010cm−2eV−1. In order to improve the N+ source/drain activation efficiency, the Si∕P coimplantation technique was adapted to fabricate GaAs n-type metal-oxide-semiconductor field-effect-transistor (MOSFET). High quality N+∕P GaAs junction was achieved with extremely low junction leakage current of 3×10−6A∕cm2 at reverse bias of 1V and high forward current to reverse current ratio of Iforward∕Ireverse∼107 at GaAs source/drain junction. GaAs n-MOSFETs integrated with HfO2 gate dielectric and TaN gate electrode were fabricated by using AlN passivation layer and Si∕P coimplantation techniques. The results show that our GaAs n-MOSFETs operate in enhancement mode with Ion∕Ioff ratio of approximately six orders and good transfer and output characteristics.