Calvin Leung

Morphological and Electrical Characterization of Electrically Trimmable Thin-Film Resistors

SiCr-based thin-film resistors with low temperature coefficient of resistance (TCR) have been integrated in a 0.8-μm BiCMOS technology in a dual thin-film structure, with a heater close to the thin-film resistor. Such a structure allows modifying the thin-film resistance by applying electric pulses to the heater (trimming). The morphology and the electrical properties of the as-deposited and modified thin-film resistors have been studied through transmission electron microscopy analyses and electrical measurements as a function of temperature. Structural analyses have shown the formation of Cr-rich layers at the interfaces. The experimentally observed resistance reduction upon trimming and the TCR variation have been both successfully reproduced by considering the effective medium approximation and by treating the film as a mixture of two materials with different compositions and conductivities.

Reliability analysis of CrSi Thin Film Resistors

CrSi Thin Film Resistor (TFR) is mainly used due to its high precision of less than 1% standard deviation and low thermal coefficient of resistance (TCR) with zero drift with temperature. Reliability characterization is studied on CrSi Thin Film Resistors (TFRs) to understand the reliability behaviour of CrSi Thin Film Resistors. Current sweep is performed on TFRs structures to determine current density threshold before catastrophic resistance degradation. Constant Current stress is performed at several currents to characterize the resistance change of TFRs with current. 2 models are proposed for lifetime stability prediction of TFRs.