Effect of V-shaped geometries on the electrothermal response and burst behavior of Ni–Cr thin-film bridge chips

Ni–Cr thin-film bridge chips are electrothermal devices whose transient response is strongly influenced by bridge geometry. In this work, the electrothermal characteristics of Ni–Cr thin-film bridge chips with different V-shaped geometries were systematically investigated. Four bridge configurations with V-shaped angles of 180°, 150°, 120°, and 90° were fabricated under controlled electrical and dimensional conditions, where the initial bridge resistance and bridge length were kept identical to investigate the influence of V-shaped geometric variation on transient electrothermal behavior. Electrothermal simulations using COMSOL Multiphysics were performed to investigate how V-shaped geometric variation affects hotspot formation at the V-shaped corner and the early-stage temperature-rise rate under the investigated excitation condition. Short-pulse constant-current experiments were conducted to obtain voltage–time traces that capture the bridge burst process. Based on these results, a simulation-based burst time metric t e,sim was extracted from the global maximum temperature history using a predefined temperature-threshold criterion for comparative analysis, and the experimental burst time t e was obtained from the onset of the abrupt resistance jump in the voltage–time traces. Both simulations and experiments show that reducing the V-shaped geometric variation affects the burst time, and the measured t e exhibits a consistent trend with t e,sim within a limited deviation. Under the investigated material system, excitation condition, and dimensional range, t e decreases as the V-shaped geometric constriction increases from the rectangular bridge configuration to the 90° V-shaped configuration. These results provide experimental insights into the geometry-dependent transient electrothermal response characteristics of Ni–Cr thin-film bridge chips.