Characteristics of ZrO₂ gate dielectrics on O₂- and N₂O-plasma treated partially strain-compensated Si _0.69Ge_0.3C_0.01 layers

The characteristics of ZrO₂ gate dielectric along with the interfacial layer on O₂- and N₂O-plasma treated partially strain-compensated Si_0.69Ge_0.3C_0.01/Si heterostructures have been investigated using spectroscopic and electrical measurements. Time-of-flight secondary ion mass spectroscopy and x-ray photoelectron spectroscopy analyses show the formation of an oxygen or nitrogen rich Zr-germanosilicate interfacial layer between the deposited ZrO₂ and SiGeC films. The electrical and charge trapping properties under a constant current stressing have been studied using a metal-oxide-semiconductor structure. The N₂O-plasma treated SiGeC film has a higher effective dielectric constant (k ~ 14) than that of the O₂-plasma treated (k~ 12) films. The equivalent areal densities of charge defects, N_eq (cm ^-2), are found to be ∼ 1.8 × 10¹² and ∼6 × 10¹¹ cm^-2 for O₂- and N ₂O-plasma treated films, respectively. Considerably less trapped charges in the N₂O-treated gate dielectric stack under constant current stressing make it highly attractive for SiGeC based scaled metal-oxide-semiconductor device applications.