Cyclic Plasma Treatment during ALD Hf_(1-x)Zr_xO_2 Deposition

摘要

Effect of slot plane antenna (SPA) Ar plasma on the reliability of intermediate plasma (DSDS) treated ALD Hf_(1-x)Zr_xO_2 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-k 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 HfO_2 and ZrO_2 and Zr variation seems to contribute to the improvement in DSDS Hf_(1-x)Zr_xO_2 (x = 0.8) by suppressing the oxide trap formation as observed in the Weibull characteristics. DSDS Hf_(1-x)Zr_xO_2 with x = 0.8, therefore, demonstrates a superior equivalent oxide thickness (EOT) downscaling ability and good reliability performance.