| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a data writing method capable of executing data writing where a sufficient large threshold voltage difference between the charge storage time and the charge nonstorage time of a floating gate even when a resistance between a source and a drain is 20 kΩor more. <P>SOLUTION: According to this data writing method, first, a voltage between a source and a drain is applied to the source and drain diffusion areas 103 and 104 of a semiconductor memory device 100 via a bit line. A pulse voltage is applied to a control gate 108. For this pulse voltage, time LEE necessary from a 0 volt to a last writing voltage (e.g., 5 to 8 volts) is set to 7 to 10 microseconds, and time Width maintained for the last writing voltage is set to 30-LEE microseconds. Thus, without reducing a writing speed, a threshold voltage difference between memory devices is set sufficiently high. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
