NOVELTY - The moisture barrier (100) has an interfacial layer (104) associated with a polymer layer (102), where a barrier layer (106) is associated with the interfacial layer. The polymer layer includes one of polyethylene terephthalate, polyethylene naphthalate and ethylene-tetrafluoroethylene. The interfacial layer is formed by atomic layer deposition (ALD), where an ALD interfacial layer includes one of aluminum oxide or titanium oxides. The ALD interfacial layer is deposited at temperature of less than 100 and 150 degree Celsius.    USE - Thin film moisture barrier for packaging a sensitive device i.e. photovoltaic cell (claimed). Can also be used for integrated circuit devices, photonic devices, batteries, piezoelectric devices, micro-electromechanical systems, sensors, actuators, flat panel displays, food, pharmaceuticals, consumer goods and cosmetics.    ADVANTAGE - The moisture barrier protects the device or substrate from water, water vapor or other substances present in the environment which can serve to degrade or damage the device or substrate. The barriers can be used to enhance packaging outside of the field of electronics, pharmaceutical blister packs, food packaging and similar materials. The layers can be inserted in the stack construction between the encapsulant and window layers so as to protect the window layer against harmful encapsulant degradation products or adverse effects related to window layer exposure to moisture or other substances potentially present in the installation environment or together with a tandem overlying moisture barrier.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a device i.e. photovoltaic cell, comprising a device substrate    (2) a method for forming a moisture barrier.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of a thin film moisture barrier.    Thin film moisture barrier (100)    Polymer layer (102)    Interfacial layer (104)    Barrier layer (106)    Substrate (108)