| 摘要 |
<p>A nonvolatile semiconductor memory cell, and a method for writing data therein are provided to prevent the semiconductor memory cell from being deteriorated due to a detrapping phenomenon of electric charges, even if a dielectric film with a relatively high dielectric constant serves as a gate dielectric film, using a detrapping pulse signal. In a data-writable memory cell transistor, a floating gate(3) is deposited on a semiconductor substrate(1) so that a first dielectric film(2) is sandwiched between the floating gate and the semiconductor substrate, and a control gate(6) is deposited on the floating gate so that a second dielectric film(5) is sandwiched between the control gate and the floating gate. Firstly, a writing voltage is applied to the control gate so that the memory cell transistor turns to be in a written state. Data is read out from the written memory cell transistor so that a verification for the written state is performed. If the written state of the memory cell transistor is verified, a detrapping pulse signal is applied to the control gate so that electric charges are extracted from the second dielectric film.</p> |
