| 摘要 |
<p>In a method of applying a voltage pulse for injecting/extracting electrons into/from a non-volatile semiconductor memory in which high and low levels of a threshold voltage corresponding to presence and absence of storage of electrons are caused to correspond to binary information, the method includes the steps of generating a plurality of voltage pulses each having an ability of injecting or extracting only a portion of all electrons to be stored, and applying the plurality of voltage pulses to the non-volatile semiconductor memory to thereby carry out injection/extraction of all the electrons. Since the pulse of a Fowler-Nordheim current flowing through the tunnel insulating film by one voltage pulse is short, the density of holes produced in the tunnel insulating film by such a current pulse is extremely low. As a result, the number of holes trapped by a plurality of Fowler-Nordheim current pulses caused to flow by a plurality of voltage pulses is reduced, so the life time of the tunnel insulating film is prolonged.</p> |
