Cyclic Plasma Treatment during ALD Hf1-xZrxO2 Deposition

Abstract

Effect of slot plane antenna (SPA) Ar plasma on the reliability of intermediate plasma (DSDS) treated ALD Hf1-xZrxO2 samples with x = 0, 0.31, 0.8 were investigated. The metal oxide semiconductor capacitors (MOSCAP) were subjected to a constant field stress of 27.5 MV/cm in the gate injection mode and the stress-induced flatband voltage shifts and stress induced leakage currents were monitored. The dielectric film deposited without any intermediate step (As-Dep), having the same number of atomic layer deposition (ALD) cycles as DSDS samples was used as the control sample. It was observed that plasma exposure enhances the quality of high-κ film by reducing the number of intrinsic traps in the film and Zr addition further enhances the reliability. Breakdown characteristics also confirm this behavior. Electron affinity variation in HfO2 and ZrO2 and Zr variation seems to contribute to the improvement in DSDS Hf1-xZrxO2 (x = 0.8) by suppressing the oxide trap formation as observed in the Weibull characteristics. DSDS Hf1-xZrxO2 with x = 0.8, therefore, demonstrates a superior equivalent oxide thickness (EOT) downscaling ability and good reliability performance.