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

Abstract

Ge metal-oxide-semiconductor (MOS) capacitor with YON/ LaON, as interface passivation layer (IPL), and HfO 2 , as gate dielectric, is proposed to take advantage of both the good passivation effect by LaON and the suppressed intermixing between HfO 2 and 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 Â 10 11 cm À2 eV À1 ) and oxidecharge density (À4.18 Â 10 12 cm À2 ), small gate leakage current (1.15 Â 10 À4 A cm À2 at V g ¼ V fb þ 1 V), and good high-field reliability.Schematic diagram (a) and C-V curves (b) of the gate stack with YON/LaON dual IPL.