The triangular voltage sweep (TVS) technique has been traditionally used for mobile ion detection in gate oxides. In this paper, we present and discuss the results of TVS measurements on plasma enhanced chemical vapor deposited (PECVD) silicon oxide and a low dielectric constant hybrid organosiloxane polymer (HOSP). A variety of gate metals were studied to detect and separate mobile ion effects associated with the metal. For the PECVD oxide, no peak was detected with Al gate metal, whereas a large peak was detected with Cu; allowing us to correlate the observed peak to mobile copper ions. TVS traces revealed no peak for Pt/HOSP capacitors, but peaks were detected with Cu, Ta, and Al capacitors. Thus, the appearance of mobile ion peaks in the TVS traces correlated well with the previously published bias-temperature stressing (BTS) induced instability of these capacitors, where the flatband voltage shifts during BTS were in the order Pt < Cu < Ta < Al, with no shift observed for Pt capacitors. The effects of temperature, voltage sweep rate, and bias hold time were also investigated for Al/HOSP and Cu/HOSP capacitors. Cu peaks were one to two orders of magnitude smaller than Al peaks under all conditions investigated. It was concluded that the peaks originate from the gate metal.