Limits of residual stress in Cr films sputter deposited on biased substrates

Stress evolution in thin Cr films on Si substrates is studied as a function of substrate bias. With increasing bias voltage, the tensile stress is observed to increase to a maximum, transition to compressive stress that also reaches a maximum. We relate the tensile stress maximum to the maximum in attractive interatomic forces between the coalescing islands, and the compressive stress maximum to the saturation in Frenkel defect concentration, with smaller contribution from entrapped Ar. We show that the maxima in both tensile and compressive residual stress correspond to the film yield strength. Compressive yield strength is higher as compared to tensile due to hardening from point defects. (C) 1999 American Institute of Physics. [S0003-6951(99)04045-0].