In a NAND type nonvolatile memory device, a first insulating layer covers a common drain region formed in a string active region and a peripheral active region. The recording system directly records the videoaudio on a plurality of independent digital recorders in real time to produce a plurality of original recordings in contrast to prior efforts which require pre-forming of tracks through a sequentially numbered mastering process for the digital media and then sending the mastered tracks to the digital media for recording, with the attendant time loss. Each side panel has hook trough and lump. The method further includes determining at least one first averaged curve peak position based on the first averaged curve and a threshold. Thus an MOS transistor with a sufficiently improved current driving capability can be fabricated on the semiconductor wafer with the two wafers positioned in crystal directions shifted from each other.