Effective passivation of HfO₂/Ge interface by using nitrided germanate as passivation interlayer

KGaA, Weinheim Ge metal-oxide-semiconductor (MOS) capacitor with YON/LaON, as interface passivation layer (IPL), and HfO2, as gate dielectric, is proposed to take advantage of both the good passivation effect by LaON and the suppressed intermixing between HfO2and Ge by YON. As a result, superior interfacial and electrical properties are obtained, as compared to samples with only YON or LaON as IPL: high k value (19.5), low interface-state density (6.64 × 1011cm−2eV−1) and oxide-charge density (−4.18 × 1012cm−2), small gate leakage current (1.15 × 10−4A cm−2at Vg= Vfb+ 1 V), and good high-field reliability. Schematic diagram (a) and C–V curves (b) of the gate stack with YON/LaON dual IPL.