A nonvolatile memory structure includes a substrate having thereon a first, a second, and a third OD regions arranged in a row. The first, second, and third OD regions are separated from one another by an isolation region. The isolation region includes a first intervening isolation region between the first OD region and the second OD region, and a second intervening isolation region between the second the third OD region. A first select transistor is formed on the first OD region. A floating gate transistor is formed on the second OD region. The floating gate transistor is serially coupled to the first select transistor. The floating gate transistor includes a floating gate completely overlapped with the second OD region and is partially overlapped with the first and second intervening isolation regions. A second select transistor is on the third OD region and serially coupled to the floating gate transistor.