Anomalous ${C}$ – ${V}$ Inversion in TSVs: The Problem and Its Cure

The metal-insulator-semiconductor capacitor formed by a through-silicon via (TSV) with its insulating layer and the p-type Si substrate may show an anomalous inversion behavior in the C-V characteristic. The dominant cause is the presence of positive charges in the backside (BS) passivation layer. In this paper, a dedicated test structure is proposed and characterized to confirm this hypothesis. Furthermore, a charge-free oxide/nitride BS passivation layer for preventing the anomalous C-V inversion, proposed in our previous work, is validated by experimental results on TSV structures manufactured up to the complete BS metallization processing.