Anomolous IV behavior of ATLAS SCT microstrip sensors

We observe deteriorated IV, leakage-to-voltage, characteristics when the ATLAS SemiConductor Tracker (SCT) silicon microstrip detector is biased at a fixed voltage Vk for a long period. The leakage current is nearly halved at voltages below Vk. The noise figure is deteriorated and signal charge spreads to neighboring strips. The detector performance is, however, not degraded when biased at or above Vk. We characterize the observed phenomena in detail in this article.