Abstract: The present invention includes a programmable thin film filament resistor and method of constructing same. The finished construction includes: a core member of hydrogenated amorphous silicon; upper and lower electrodes made of a barrier metal such as molybdenum or tungsten applied to the upper and lower surfaces of the core member; and, backing layers, typically made of aluminum, applied to the outside surfaces of the electrodes. An insulator may be added to the upper surface of the core member. A programming voltage is applied to the electrodes, creating a discharge path between the upper and lower electrodes. When a critical current is reached, a filament is formed as the aluminum of the backing layers, the barrier metal of the electrodes, and the amorphous silicon are fused together. The result is a filament resistor with linear properties within a defined operating range. In an alternate embodiment, the upper and lower electrodes are overlapped in an alternating pattern, creating fusion zones.