A semiconductor device includes a substrate, an insulating film provided on a surface of the substrate, and a sensing film formed of a conductive material deposited on top of the insulating film. The sensing film defines at least one conductive path between a first position and a second position on the insulating film. A first circuit connection is electrically connected to the sensing film at the first position on the insulating layer, and a second circuit connection is electrically connected to the sensing film at the second position. A control circuit is operatively connected to the first circuit connection and the second circuit connection for measuring an electrical resistance of the sensing film. The sensing film has a thickness that enables a resistivity of the sensing film to be altered predictably in a manner that is dependent on ambient moisture content.