Internal Stress and Electrical Properties of Ceramic Thin Film Prepared by Sol-Gel Method

We have prepared ceramic thin films on a glass substrate by a sol-gel method. Film thickness can be controlled by a set of operating conditions. Base sheet, however, is needed because those films are very thin. In this case internal stress certainly occurs in a thin film in every material. Internal stress is the cause of crack and exfoliation.Stress in sol-gel coating films was mainly tensile. It decreased with an increase of film thickness. This trend was opposite to those observed in sputter and vacuum evaporation methods.The occurrence cause of stress was that volume shrank with the decrease of pore at heat treatment. This was confirmed from the BET value at heat treatment temperature. Resistivity was not dependent on stress but on the occurrence cause of stress.