A cell array portion of a single-layer gate EEPROM device includes a plurality of unit cells formed over a substrate to share a first well region in the substrate. The photovoltaic device includes a first electrode and a second electrode disposed opposite to each other, a photoactive layer disposed between the first electrode and the second electrode, and a buffer layer disposed between the photoactive layer and the second electrode. Another aspect of the invention include a method of manufacturing the foil bridge and application to autoignition vehicle airbags. When the numbers differ from one another, a fault message and identified machine parts as possible fault sources are displayed. Phase slowness coherence is extracted from the recorded waveforms after transformation to the frequency domain at various frequencies, and this is converted into a formation slowness curve which can be used as an objective function from which an anomaly, such as a local maximum or minimum, can be identified as representative of an estimate of the formation slowness. Therefore, the efficiency of the PDP is naturally improved.